The Advisory Board Company

Exhibit 10.1

The Advisory Board Company
0000 X. XXXXXX, XX
XXXXXXXXXX, XX 00000
TELEPHONE 000-000-0000				Xxxxxx Xxxxxxxxxxx
FACSIMILE 000-000-0000		February 4, 2010		Chief Executive Officer

Xxxxxx X. Xxxxxxx, III
Chairman of the Board and Chief Executive Officer
The Corporate Executive Board Company
0000 Xxxxx Xxxx Xxxxxx
Xxxxxxxxx, XX 00000

      Re: Collaboration Agreement, dated as of February 6, 2007, by and between The Corporate Executive Board Company and The Advisory Board Company (the “Collaboration Agreement”)

Dear Xxx:

     This letter confirms that The Corporate Executive Board Company (“CEB”) and The Advisory Board Company (“ABCO”) have agreed to extend the Initial NP Term and the Initial EC Term (as such terms are defined in the Collaboration Agreement) through February 5, 2012 as contemplated by Sections 3.3(a) and 3.4(a) of the Collaboration Agreement, respectively, effective as of February 4, 2010.

     Please indicate your agreement with the foregoing by signing and returning one copy of this letter to my attention, which shall constitute CEB’s and ABCO’s agreement with respect to the subject matter hereof.

Very truly yours,

Xxxxxx X. Xxxxxxxxxxx

Chief Executive Officer

ACCEPTED AND AGREED:

THE CORPORATE EXECUTIVE BOARD COMPANY

By:
		Xxxxxx X. Xxxxxxx, III
		Chairman of the Board and Chief Executive Officer