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                                                                   EXHIBIT 10.29


                                    GUARANTY

       THIS GUARANTY (the "Guaranty"), is made as of the ______ day of
_________________ by the undersigned party (the "Guarantor"), having a notice
address at The Watergate, 600 New Hampshire Avenue, N.W., Washington, D.C. 20037
Attention: Michael A. D'Amato to and for the benefit of The George Washington
University (the "Landlord"), having a notice address of c/o LaSalle Partners
Management Services, Inc., Suite 2400, 2000 Pennsylvania Avenue, N.W.,
Washington, D.C. 20006 and Office of Vice President & Treasurer, 2121 Eye
Street, N.W., Suite 701, Washington, D.C. 20052.

       WHEREAS, the Landlord has leased to THE CORPORATE ADVISORY BOARD COMPANY,
a Delaware corporation (the "Tenant"), under a lease dated June , 1998 (herein
called the "Lease"), certain space located in 2000 K Street, N.W. (the
"Property"); and

       WHEREAS, Guarantor and Tenant are both currently sharing space at The
Watergate, 600 New Hampshire Avenue, N.W. ("The Watergate") and are affiliated
corporations; and

       WHEREAS, Guarantor and Tenant have exceeded the capacity of the space at
The Watergate and therefore, Guarantor has asked Tenant to relocate; and

       WHEREAS, Tenant has agreed to relocate and has executed the Lease for
space in 2000 Pennsylvania Avenue, N.W. and the Landlord under such Lease is
willing to let space to Tenant only on the condition that Guarantor agree to
execute and deliver this guaranty.

       WHEREAS, Guarantor will receive a benefit from the ability of Tenant to
relocate to the premises demised by the Lease in the form of additional space at
the site where Guarantor presently leases space, and Guarantor is therefore
willing to execute and deliver this Guaranty.

       NOW THEREFORE, in consideration of the premises, and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the Guarantor agrees with the Landlord as follows:

       1.     The Guarantor unconditionally and irrevocably guarantees that all
sums stated in the Lease to be payable by the Tenant or sums equal thereto will
be promptly paid in full when due in accordance with the Lease, and that the
Tenant will perform and observe each and every covenant, agreement, term and
condition in the Lease required to be performed or observed by the Tenant.
Guarantor further unconditionally and irrevocably guarantees payment to Landlord
on demand any amounts which are paid to Landlord by the Tenant pursuant to the
Lease and which are subsequently set aside as preferential transfers under
Section 547 of the Bankruptcy Code. This Guaranty is irrevocable, unconditional
and absolute, and if for any reason any such sums shall not be paid promptly
when due, the Guarantor will, promptly after notice thereof and prior to the
expiration of any period of grace provided for in said instruments for the
making of payment of any such sums, pay the same to the person entitled thereto
pursuant to the Lease regardless of (a) any defenses or rights of set-off or
counterclaims which the Tenant may have or assert against the Landlord;
provided, however, that any such payment by the Guarantor shall not constitute a
waiver of any defense or claim which the Tenant may have against the Landlord,
(b) whether the Landlord shall have taken any steps to enforce any rights
against the Tenant or any


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other person to collect such sum or any part thereof, (c) the termination of the
Lease or the enforcement of any other remedy thereunder as a result of the
default of the Tenant thereunder, or (d) any other condition or contingency. The
Guarantor also agrees to pay to such person such further amount as shall be
sufficient to cover the cost and expense of collecting such sums or any part
thereof or of otherwise enforcing this Guaranty, including, in any case,
reasonable compensation to its attorneys for all services rendered in connection
therewith. Upon the Tenant's failure to perform or observe any covenant,
agreement, term or condition in the Lease to be performed or observed by the
Tenant, the Guarantor will, promptly after notice thereof and prior to the
expiration of any period of grace provided for in any said instrument for the
performance or observance of the same, perform and observe the same or cause the
same promptly to be performed and observed.

       2.     (a)    The obligations, covenants, agreements and duties of the
Guarantor under this Guaranty shall in no way be affected or impaired by reason
of the happening from time to time of any of the following, although without
notice to or the further consent of the Guarantor:

              (i)    the waiver by the Landlord of the performance or observance
       by the Tenant, the Guarantor or any other party or parties of any of the
       agreements, covenants, terms or conditions contained in the Lease or this
       Guaranty; or

              (ii)   the extension, in whole or in part, of the time for payment
       by the Tenant or the Guarantor of any sums owing or payable under the
       Lease or this Guaranty, or of any other sums or obligations under or
       arising out of or on account of the Lease or this Guaranty, or the
       renewal of the Lease or this Guaranty; or

              (iii)  any assignment of the Lease or subletting of the Property
       or any part thereof; or

              (iv)   the modification or amendment (whether material or
       otherwise) of any of the obligations of the Tenant or the Guarantor under
       the Lease or this Guaranty; or

              (v)    the doing or the omission of any of the acts referred to in
       the Lease or this Guaranty (including, without limitation, the giving of
       any consent referred to therein); or

              (vi)   any failure, omission or delay on the part of the Landlord
       to enforce, assert or exercise any right, power or remedy conferred on or
       available to the Landlord in or by the Lease or the Guaranty, or any
       action on the part of the Landlord granting indulgence or extension in
       any form whatsoever; or

              (vii)  the voluntary or involuntary liquidation, dissolution, sale
       of all or substantially all of the assets, marshaling of assets and
       liabilities, receivership, conservatorship, insolvency, bankruptcy,
       assignment for the benefit of creditors, reorganization, arrangement,
       composition or readjustment of, or other similar proceeding affecting the
       Tenant or the Guarantor or any of their assets; or

              (viii) the release of the Tenant or the Guarantor from the
       performance or observance of any of the agreements, covenants, terms or
       conditions contained in the Lease or this Guaranty by operation of law.



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              (b)    Guarantor further covenants and agrees that neither its
obligation to make payment in accordance with the terms of this Guaranty nor any
remedy for the enforcement thereof shall be impaired, modified, changed,
released or limited in any manner whatsoever by any impairment, modification,
change, release or limitation of the liability of Tenant or its estate in
bankruptcy or any remedy for the enforcement thereof resulting from the
operation of any present or future provision of the Bankruptcy Reform Act of
1978 or other statute, or from the decision of any court, nor shall such
obligation or remedy for enforcement be impaired, modified, changed, released or
limited in any manner by such event of bankruptcy.

              (c)    The Guarantor hereby expressly waives, to the extent not
prohibited by law, for itself and all those claiming under the Guarantor (i) any
right the Guarantor may now or hereafter have to require the Landlord to proceed
first against the Tenant upon any obligation or liability of the Tenant that is
guaranteed by the Guarantor hereunder, (ii) any right the Guarantor may now or
hereafter have to any hearing prior to the attachment of any real or personal
property of the Guarantor to satisfy the obligations of the Guarantor hereunder,
and (iii) the benefits of any present or future constitution, statute or rule of
law which exempts property from liability for debt.

       3.     In the event of the rejection or disaffirmance of the Lease by the
Tenant or the Tenant's trustee in bankruptcy pursuant to bankruptcy law or any
other law affecting creditors' rights, the Guarantor will, and does hereby
(without the necessity of any further agreement or act), assume all obligations
and liabilities of the Tenant under the Lease to the same extent as if (a)
Guarantor were originally named the Tenant under the Lease, and (b) there had
been no such rejection or disaffirmance, and the Guarantor will confirm such
assumption in writing at the request of the Landlord upon or after such
rejection or disaffirmance; the Guarantor shall, upon such assumption (to the
extent permitted by law), have all rights of the Tenant under the Lease.

       4.     Notice of acceptance of this Guaranty and notice of any
obligations or liabilities contracted or incurred by the Tenant are hereby
waived by the Guarantor.

       5.     This Guaranty may not be modified or amended except by a written
agreement duly executed by the Guarantor with the consent in writing of the
Landlord.

       6.     The Guarantor hereby covenants and represents that (a) neither the
execution, delivery or performance of this Guaranty or the Lease, nor the
consummation of the transactions herein or therein contemplated, nor compliance
with the terms and provisions hereof or thereof conflicts or will conflict with
or result or will result in a breach of or constitutes or will constitute a
default under (i) the organizational documents or other charter documents or
by-laws, if any, of the Tenant, (ii) any law or any order, writ, injunction or
decree of any court or governmental authority or (iii) any agreement or
instrument to which the Guarantor or the Tenant is a party or by which Guarantor
or the Tenant is bound; (b) the Guarantor is not engaged in any litigation which
will or may adversely affect its ability to carry out any of the terms and
provisions of this Guaranty.

       7.     This is an unconditional guaranty of payment, not merely of
collection. The Guarantor's liability hereunder shall be primary and not
secondary, and shall be joint and several with that of the Tenant. The Landlord
may proceed against the Guarantor under this Guaranty



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without initiating or exhausting its remedy or remedies against the Tenant, and
may proceed against the Tenant and/or the Guarantor separately or concurrently.
If more than one party constitutes Guarantor, then all obligations and covenants
set forth herein shall be the joint and several obligations and covenants of the
undersigned parties collectively constituting Guarantor.

       8.     The Guarantor hereby warrants and represents that as of the date
hereof, there has been no material change in its financial condition from that
reflected in any financial statements previously submitted to Landlord, and
since the date of such statement, if any, the business, property and assets of
the Guarantor have not been adversely affected in any way.

       9.     If any term or provision of this Guaranty shall be determined to
be illegal or unforceable, all other terms and provisions hereof shall
nevertheless remain effective and shall be enforced to the fullest extent
permitted by law.

       10.    Any notice which the Landlord may elect to send to the Guarantor
shall be binding upon the Guarantor if mailed to it at the address set forth
above or its last address known to the Landlord, by United States Certified or
Registered Mail, Return Receipt Requested.

       11.    This Guaranty shall be construed in accordance with the laws of
the District of Columbia. Guarantor agrees that any litigation arising out of,
or related to, this Guaranty or the Lease shall be brought in the courts of the
District of Columbia or in the United States District Court for the District of
Columbia, and the Guarantor hereby consents to the venue of such courts.
Guarantor consents to service of process and any pleading relating to any action
between Landlord and Guarantor at the Demised Premises, as defined in the Lease,
provided however, that nothing herein shall be construed as requiring such
service at the Demised Premises.

       12.    This Guaranty shall be binding upon, Guarantor, its heirs,
personal representatives, successors and assigns and shall inure to the benefit
of, Landlord, its successors and assigns.

       13.    This Guaranty shall expire on March 31, 2002 provided the
following conditions have been met:

              (a)    The Tenant is not then in default under the Lease.

              (b)    Guarantor has provided to Landlord audited financial
statements for The Corporate Advisory Board Company prepared by Arthur Anderson
or other national accounting firm acceptable to Landlord in its reasonable
discretion for two (2) consecutive Fiscal Years ending December 31 which show
for each such Fiscal Year that the lesser of operating income or income before
provision of income taxes (after option repurchase and non-recurring
compensation and interest income as shown on such financial statements) exceeds
ten million dollars ($10,000,000).

              (c)    The second of the two (2) consecutive Fiscal Years referred
to above ends on December 31, 2001.

              (d)    Landlord has confirmed, within ten (10) business days of
the submission of the financial statements referenced in (b). above that for
each Fiscal Year shown on such



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financial statements that the lesser of operating income or income before
provision of income taxes (after option repurchase and non-recurring
compensation and interest income as shown on such financial statements) exceeds
ten million dollars ($10,000,000) and that the Tenant is not in default under
the Lease.

              (e)    The financial statements are delivered to Landlord no later
than March 15, 2002.

In the event that the financial statements required under subparagraph (b) are
submitted for years subsequent to Fiscal Year 2001, then the Guaranty will
expire on the first day of the month following the month in which Landlord
confirms the information in such financial statements as required in
subparagraph (d) above. In the event that the financial statements for Fiscal
Years 2000 and 2001 are submitted to Landlord later than March 15, 2002, then
the Guaranty will not expire until the first day of the month following the
month in which Landlord confirms the information in the financial statements
required by subparagraph (d) above.

       The date of the expiration of this Guaranty is referred to herein and in
the Lease as the "Burnoff Date".

       IN WITNESS WHEREOF, the Guarantor has caused this Guaranty to be executed
as of the date first above written.


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                                       GUARANTOR:

Attest/Witness:                        THE ADVISORY BOARD COMPANY


<S>                                    <C>
                                       By:                               (SEAL)
--------------------------------           ------------------------------
Assistant Secretary                         President
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