JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(l) under the Securities Exchange Act of 1934, as amended, each of the undersigned hereby agrees to the joint filing, along with all other such undersigned, on behalf of the Reporting Persons (as defined in the joint filing), of a statement on Schedule 13D (including amendments thereto) with respect to the common stock of Borders Group, Inc., and that this agreement be included as an Exhibit to such joint filing.  This agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.

[signatures on following page]

IN WITNESS WHEREOF, each of the undersigned has executed this agreement as of this 14th day of April, 2008.

PERSHING SQUARE CAPITAL MANAGEMENT, L.P.
By:	PS Management GP, LLC,
	its General Partner
By:	­/s/ William A. Ackman
	William A. Ackman
	Managing Member
PS MANAGEMENT GP, LLC
By:	/s/ William A. Ackman
	William A. Ackman
	Managing Member
PERSHING SQUARE GP, LLC
By:	/s/ William A. Ackman
	William A. Ackman
	Managing Member
/s/ William A. Ackman
William A. Ackman
BGP HOLDINGS CORP.
By: /s/ William A. Ackman William A. Ackman Authorized Representative