UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13D

                   UNDER THE SECURITIES EXCHANGE ACT OF 1934

                               (AMENDMENT NO. 3)*

                           ART TECHNOLOGY GROUP, INC.
--------------------------------------------------------------------------------

                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                             CUSIP NO. 458727 20 3
--------------------------------------------------------------------------------
                                 (CUSIP Number)

James H. Dennedy                           Richard S. Rofe
Mitchell-Wright Technology Group, LLC      Mitchell-Wright Technology Group, LLC
8060 Montgomery Road, Suite 205            185 Great Neck Road, Suite 460
Cincinnati, OH 45236                       Great Neck, NY 11020
--------------------------------------------------------------------------------

(513) 792-5100                             (516) 466-5258
--------------------------------------------------------------------------------


--------------------------------------------------------------------------------
                  Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications

                               September 28, 2004
--------------------------------------------------------------------------------
                          (Date of Event Which Requires
                            Filing of This Statement)

         If the person filing has previously filed a statement on Schedule 13G
to report the acquisition that is the subject of this Schedule 13D, and is
filing this schedule because of ss. 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g),
check the following box. |_|

         NOTE: Schedules filed in paper format shall include a signed original
and five copies of the schedule, including all exhibits. See Rule 13d-7 for
other parties to whom copies are to be sent.

         *The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.

         The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however, see
the Notes).






                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 2 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         SSH Partners I, LLP

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to
         Items 2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        125,000
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        0
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        125,000
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        0
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         125,000

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.2%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         PN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 3 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Mitchell-Wright Technology Group, LLC             41-2142179

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        125,000
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        0
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        125,000
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        0
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         125,000

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.2%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!






                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 4 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Mitchell-Wright, LLC

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        125,000
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        0
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        125,000
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        0
------------------------------------------------------------ -------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         125,000

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.2%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!






                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 5 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         James Dennedy

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) PF/AF

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         USA

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        145,000
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        0
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        145,000
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        0
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         145,000

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.2%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         IN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!





                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 6 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Arcadia Partners, L.P.

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        36,744
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        0
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        36,744
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        0
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         36,744

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.0%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         PN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 7 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Arcadia Capital Management, LLC

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        36,744
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        0
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        36,744
                                               ---------------------------------
                                               (10)     Shared Dispositive Power
                                                        0
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         36,744

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.0%

--------------------------------------------------------------------------------
(14) Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 8 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Richard Rofe

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         USA

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        172,244
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        0
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        172,244
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        0
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         172,244

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.2%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         IN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!





                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                         PAGE 9 OF 21 PAGES

--------------------------------------------------------------------------------
(1)       Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Parche, LLC                                 20-0870632

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        643,176
                                               ---------------------------------
                                               (9)      Sole Dispositive Power


                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        643,176
------------------------------------------------------------ -------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         643,176

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         0.9%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 10 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Starboard Value & Opportunity Fund, LLC

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        3,376,680
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        3,376,680
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         3,376,680

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         4.6%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 11 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Admiral Advisors, LLC

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        4,019,856
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        4,019,856
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         4,019,856

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         5.4%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 12 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Ramius Capital Group, LLC

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        4,019,856
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        4,019,856
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         4,019,856

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         5.4%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 13 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         C4S & Co., LLC

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         Delaware

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        4,019,856
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        4,019,856
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         4,019,856

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         5.4%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         OO

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 14 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Peter A. Cohen

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         USA

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        4,019,856
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        4,019,856
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         4,019,856

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         5.4%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         IN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 15 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Morgan B. Stark

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         USA

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        4,019,856
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        4,019,856
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         4,019,856

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         5.4%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         IN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 16 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Jeffrey M. Solomon

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         USA

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        4,019,856
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        4,019,856
------------------------------------------------------------ -------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         4,019,856

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         5.4%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         IN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!




                                  SCHEDULE 13D
CUSIP NO. 458727 20 3                                        PAGE 17 OF 21 PAGES

--------------------------------------------------------------------------------
(1)      Names of Reporting Persons.
         S.S. or Identification Nos. of above persons (entities only).

         Thomas W. Strauss

--------------------------------------------------------------------------------
(2)      Check the Appropriate Box if a Member (a) /x/ of a Group (See
         Instructions) (b) //

--------------------------------------------------------------------------------
(3)      Sec Use Only

--------------------------------------------------------------------------------
(4)      Source of Funds (see instructions) WC

--------------------------------------------------------------------------------
(5)      Check if disclosure of legal proceedings is required pursuant to Items
         2(d) or 2(e).

--------------------------------------------------------------------------------
(6)      Citizenship or Place of Organization

         USA

--------------------------------------------------------------------------------
Number of Shares Beneficially Owned by Each    (7)      Sole Voting Power
Reporting Person with:
                                                        0
                                               ---------------------------------
                                               (8)      Shared Voting Power

                                                        4,019,856
                                               ---------------------------------
                                               (9)      Sole Dispositive Power

                                                        0
                                               ---------------------------------
                                               (10)     Shared Dispositive Power

                                                        4,019,856
--------------------------------------------------------------------------------
(11)     Aggregate Amount Beneficially Owned by Each Reporting Person
         4,019,856

--------------------------------------------------------------------------------
(12)     Check if the Aggregate Amount in Row (11) Excludes Certain Shares
         (See Instructions)  //


--------------------------------------------------------------------------------
(13)     Percent of Class Represented by Amount in Row (11)
         5.4%

--------------------------------------------------------------------------------
(14)     Type of Reporting Person (See Instructions)
         IN

--------------------------------------------------------------------------------
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!





ITEM 1.  SECURITY AND ISSUER

This Amendment No. 3 to Schedule 13D relates to shares of the Common Stock, par
value $0.01 per share ("Common Stock"), of Art Technology Group, Inc. (the
"Issuer" or the "Company") and is being filed on behalf of the undersigned to
amend the Schedule 13D which was originally filed on August 24, 2004, and
amended on September 10, 2004 and September 20, 2004 (the "Schedule 13D").
Unless otherwise indicated, all capitalized terms used herein but not defined
herein shall have the same meanings as set forth in the Schedule 13D.

ITEM 2.  IDENTITY AND BACKGROUND

This Amendment No. 3 to Schedule 13D is filed by a group consisting of SSH
Partners I, LP, Mitchell-Wright Technology Group, LLC, Mitchell-Wright, LLC,
James Dennedy, Arcadia Partners, L.P., Arcadia Capital Management, LLC, Richard
Rofe, Parche, LLC, Starboard Value & Opportunity Fund, LLC, Admiral Advisors,
LLC, Ramius Capital Group, LLC, C4S & Co., LLC, Peter A. Cohen, Morgan B. Stark,
Jeffrey M. Solomon, and Thomas W. Strauss (collectively, the "Reporting
Persons").

ITEM 3.  SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION

The additional shares of Common Stock purchased by the Reporting Persons since
the filing of the Schedule 13D, as described in Item 5 below, were made in open
market transactions. All such purchases of Common Stock by each of the Reporting
Persons were funded by working capital, which may, at any given time, include
margin loans made by brokerage firms in the ordinary course of business. The
amount of funds expended for such purchases was $21,000 by Parche, LLC, and
approximately $110,000 by Starboard Value & Opportunity Fund, LLC.

ITEM 4.  PURPOSE OF THE TRANSACTION

On September 28, 2004, Mitchell-Wright Technology Group, LLC, Mitchell-Wright,
LLC, SSH Partners I, LP, Arcadia Partners, L.P., Arcadia Capital Management,
LLC, James Dennedy and Richard Rofe filed a preliminary proxy statement with the
Securities and Exchange Commission in connection with their solicitation of
proxies against the proposal to issue shares of the Company's common stock in
connection with the proposed merger involving the Company and Primus Knowledge
Solutions, Inc. at the special meeting of stockholders of the Company to be held
on October 22, 2004 and at any adjournments or postponements thereof.

SHAREHOLDERS ARE ADVISED TO READ THE PROXY STATEMENT AND OTHER DOCUMENTS RELATED
TO SOLICITATION OF PROXIES BY MITCHELL-WRIGHT TECHNOLOGY GROUP, LLC, SSH
PARTNERS I, LP, MITCHELL-WRIGHT, LLC, JAMES DENNEDY, ARCADIA PARTNERS, L.P.,
ARCADIA CAPITAL MANAGEMENT, LLC AND RICHARD ROFE FROM THE SHAREHOLDERS OF ART
TECHNOLOGY GROUP, INC. FOR USE AT ITS SPECIAL MEETING WHEN THEY BECOME AVAILABLE
BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. WHEN COMPLETED, A DEFINITIVE
PROXY STATEMENT AND A FORM OF PROXY WILL BE MAILED TO SHAREHOLDERS OF ART
TECHNOLOGY GROUP, INC. AND WILL BE AVAILABLE AT NO CHARGE AT THE SECURITIES AND
EXCHANGE COMMISSION'S WEBSITE AT HTTP://WWW.SEC.GOV.

ITEM 5.  INTEREST IN SECURITIES OF THE ISSUER

(a), (b)

As of September 28, 2004, the aggregate number of shares of Common Stock to
which this Schedule 13D relates is 4,337,100 shares, representing 5.9% of the
73,889,870 shares of Common Stock reported by the Company to be issued and
outstanding as of September 9, 2004, in its joint proxy statement/prospectus on
Form S-4 filed with the Securities and Exchange Commission on September 22,
2004. The Reporting Persons beneficially own those shares as follows:

As of the date hereof, Parche, LLC beneficially owns an aggregate of 643,176
shares of Common Stock, representing approximately 0.9% of the shares of Common
Stock presently outstanding. In addition, by virtue of the relationships
described under Item 2 of this Schedule 13D, each of Admiral Advisors, LLC,
Ramius Capital Group, LLC, C4S & Co., Peter A. Cohen, Morgan B. Stark, Jeffrey
M. Solomon and Thomas W. Strauss may be deemed to have an indirect beneficial
ownership of all the shares of Common Stock beneficially owned by Parche, LLC.




As of the date hereof, Starboard Value & Opportunity Fund, LLC beneficially owns
an aggregate of 3,376,680 shares of Common Stock, representing approximately
4.6% of the outstanding shares of Common Stock. In addition, by virtue of the
relationships described under Item 2 of this Schedule 13D, each of Admiral
Advisors, LLC, Ramius Capital Group, LLC, C4S & Co., LLC, Peter A. Cohen, Morgan
B. Stark, Jeffrey M. Solomon and Thomas W. Strauss may be deemed to have an
indirect beneficial ownership of all the shares of Common Stock beneficially
owned by Starboard Value & Opportunity Fund, LLC.

Each of Messrs. Cohen, Stark, Solomon and Strauss shares voting and dispositive
power with respect to both the 643,176 shares of Common Stock owned by Parche,
LLC and the 3,376,680 shares of Common Stock owned by Starboard Value &
Opportunity Fund, LLC by virtue of their status as joint managing members of C4S
& Co., LLC, the Managing Member of Ramius Capital Group, LLC, which in turn is
the Managing Member of Admiral Advisors, LLC, which is the Managing Member of
both Parche, LLC and Starboard Value & Opportunity Fund, LLC.

Messrs. Cohen, Stark, Solomon, and Strauss, C4S & Co., LLC, Ramius Capital
Group, LLC and Admiral Advisors, LLC each disclaim beneficial ownership of the
shares of the Issuer's Common Stock held of record by Parche, LLC and Starboard
Value & Opportunity Fund, LLC, and the filing of this Schedule 13D shall not be
construed as an admission that any such person is the beneficial owner of any
such securities.

(c) Not applicable

(d) Not applicable

(e) Not applicable

ITEM 6.  CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT
         TO SECURITIES OF THE ISSUER

MWTG, Parche, LLC, and Starboard Value and Opportunity Fund, LLC have an
agreement pursuant to which MWTG provides advice and services with respect to
the parties' investments in the Common Stock of the Issuer, among other matters.
Under such agreement, the parties agree to coordinate the acquisition and
disposition of Common Stock of the Issuer with MWTG and to cooperate with
respect to proxy votes and related matters (however, each of the parties to the
agreement retains the sole discretion over acquisitions and dispositions of, and
voting authority over, the shares of Common Stock that it holds). For such
services, MWTG receives an amount equal to a percentage of the profits realized
by such parties on their investment in the Issuer. The parties have also agreed
to share expenses incurred by the group.

ITEM 7.  MATERIAL TO BE FILED AS EXHIBITS

None



--------------------------------------------------------------------------------

                                    SIGNATURE
         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


September 28, 2004                    SSH Partners I, LP
                                      By: Mitchell-Wright Technology Group, LLC,
                                           its General Partner
                                      /s/ James Dennedy
                                      ------------------------------------------
                                  By: James Dennedy
                                      Managing Member

September 28, 2004                    Mitchell-Wright Technology Group, LLC
                                      By:   Mitchell-Wright, LLC, its Managing
                                            Member
                                      /s/ James Dennedy
                                      ------------------------------------------
                                  By: James Dennedy
                                      Managing Member

September 28, 2004                    Mitchell-Wright, LLC
                                      /s/ James Dennedy
                                      ------------------------------------------
                                  By: James Dennedy
                                      Managing Member

September 28, 2004                    /s/ James Dennedy
                                      ------------------------------------------
                                      James Dennedy



--------------------------------------------------------------------------------
September 28, 2004                     Arcadia Partners, L.P.
                                       By: Arcadia Capital Management, LLC, its
                                           General Partner
                                       /s/ Richard Rofe
                                       -----------------------------------------
                                  By:  Richard Rofe
                                       Member

September 28, 2004                     Arcadia Capital Management, LLC
                                       /s/ Richard Rofe
                                       -----------------------------------------
                                  By:  Richard Rofe
                                       Member

September 28, 2004                     /s/ Richard Rofe
                                       -----------------------------------------
                                       Richard Rofe

September 28, 2004                     Parche, LLC
                                       By:   Admiral Advisors, LLC, its managing
                                             member
                                       /s/ Jeffrey M. Solomon
                                       -----------------------------------------
                                  By:  Jeffrey M. Solomon
                                       Authorized Signatory

September 28, 2004                     Starboard Value & Opportunity Fund, LLC
                                       By:   Admiral Advisors, LLC, its managing
                                             member
                                       /s/ Jeffrey M. Solomon
                                       -----------------------------------------
                                  By:  Jeffrey M. Solomon
                                       Authorized Signatory



September 28, 2004                    Ramius Capital Group, LLC
                                      By:   C4S & Co., LLC, its Managing Member
                                      /s/ Jeffrey M. Solomon
                                      ------------------------------------------
                                   By:Jeffrey M. Solomon
                                      Authorized Signatory

September 28, 2004                    C4S & Co., LLC
                                      /s/ Jeffrey M. Solomon
                                      ------------------------------------------
                                   By:Jeffrey M. Solomon
                                      Authorized Signatory

September 28, 2004                    /s/ Peter A. Cohen
                                      ------------------------------------------
                                      Peter A. Cohen

September 28, 2004                    /s/ Morgan B. Stark
                                      ------------------------------------------
                                      Morgan B. Stark

September 28, 2004                    /s/ Jeffrey M. Solomon
                                      ------------------------------------------
                                      Jeffrey M. Solomon

September 28, 2004                    /s/ Thomas W. Strauss
                                      ------------------------------------------
                                      Thomas W. Strauss







                                   SCHEDULE I

This schedule sets forth information with respect to each purchase and sale of
Common Stock which was effectuated by a Reporting Person since the filing of the
most recent amendment to the Schedule 13D. All transactions were effectuated in
the open market through a broker.

Parche, LLC
-----------

          Number of Shares
Date      Purchased/(Sold)      Price Per Share(1)
----      ----------------      ------------------

9/23/2004      2,400                   $0.96
9/24/2004      4,000                   $0.96
9/27/2004      5,600                   $0.93
9/28/2004     10,400                   $0.93

Starboard Value and Opportunity Fund, LLC
-----------------------------------------

          Number of Shares
Date      Purchased/(Sold)      Price Per Share(1)
----      ----------------      ------------------

9/23/2004     12,600                   $0.96
9/24/2004     21,000                   $0.96
9/27/2004     29,400                   $0.93
9/28/2004     54,600                   $0.93

(1) Excludes commissions and other execution-related costs.