Exhibit 10 (tttt)




June 30, 1997


Mr. Paul E. Gaston
Celtics Group
33 East 63rd Street
New York, NY 10021

Re:  Exchange of Options for Restricted Units

Dear Paul:

Pursuant to authorization by the Audit Committee of Celtics,  Inc., the purpose
of this letter is to permit you to elect to exchange  options to purchase units
of Boston  Celtics  Limited  Partnership  (BCLP)  granted to you under the Unit
Option  (Non-Assignable)  dated  December 31, 1993 (the Option  Agreement)  for
Restricted Units of BCLP described below. The proposed exchange of such options
for such Restricted Units has been reviewed and approved by the Audit Committee
of the Board of Celtics, Inc.

Election to Exchange Options for Restricted Units

At your request,  and with the approval of the Audit  Committee of the Board of
Directors  of  Celtics,  Inc.,  you may  elect to  receive  units  representing
assignments of beneficial  ownership of limited  partnership  interests of BCLP
subject to restrictions as set forth herein (the Restricted  Units) in exchange
for your  surrender of an equal number of units granted to you under the Option
Agreement. You may exercise this exchange right for all of the units covered by
the Option Agreement.

      (i)   Restrictions.  All Restricted  Units granted  hereunder in exchange
            for surrendered  units granted under the Option  Agreement shall be
            subject to the following restrictions.

            (a)   a required  period of  employment  with  BCLP,  or any of its
                  subsidiaries or affiliates (the "Company"), of ten (10) years
                  from the date of this  letter,  prior to the  vesting  of the
                  Restricted  Units;  (b) except for any transfer by you to any
                  partnership  of  which  you  are  the  general   partner,   a
                  prohibition against the sale, assignment,  transfer,  pledge,
                  hypothecation  or other  encumbrance of the Restricted  Units
                  for a period of ten (10) years from the date of this letter;




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            (c)   a requirement  that all such Restricted Units be forfeited in
                  the event of termination of your employment during any period
                  in which such  Restricted  Units are subject to  restriction;
                  and

            (d)   a prohibition  against your  employment by any  competitor of
                  the Company and against your  dissemination  of any secret or
                  confidential information belonging to the Company.

            All  restrictions on Restricted Units awarded pursuant hereto shall
            expire at such time or times as herein provided.

      (ii)  Registration of Restricted Units. Restricted Units awarded pursuant
            hereto  shall be  registered  in your name and, if such  Restricted
            Units are certificated, shall be deposited with the Company.

      (iii) Rights of  Holder of  Restricted  Units.  Subject  to the terms and
            conditions hereof,  during any period in which Restricted Units are
            subject to forfeiture or restrictions  on transfer,  you shall have
            all of the rights of a holder of units of BCLP (Units) with respect
            to  such  Restricted  Units,  including  the  right  to  vote  such
            Restricted  Units and the right to receive all  distributions  paid
            with respect to Units on the same basis as if the Restricted  Units
            were deemed to be Units. Any securities distributed with respect to
            Restricted Units shall be restricted to the same extent and subject
            to the same terms and conditions as the  Restricted  Units to which
            they are attributable.

      (iv)  Lapse of Restrictions.  Subject to the terms and conditions hereof,
            at the end of the time period during which the Restricted Units are
            subject to forfeiture or restrictions on transfer,  such Restricted
            Units will be delivered free of all restrictions to you (or to your
            legal representative, beneficiary or heir).

      (v)   Death; Change in Control.

            (a)   Notwithstanding any provision hereof to the contrary,  in the
                  event of your  death or in the event of a Change  in  Control
                  you,  or  your  estate,  the  beneficiaries  thereof,  or the
                  authorized  legal   representative  of  your  estate  or  the
                  beneficiaries  thereof,  as the case may be,  for a period of
                  five (5) years  from and  after  the date of your  death or a
                  Change in Control (as the case may be),  shall have the right
                  to sell all or a  portion  of the  Restricted  Units  granted
                  hereunder  to BCLP at a price and on such  other  terms to be
                  determined by the Audit Committee, based upon advice received
                  from  an  investment   banking  firm  or  financial   advisor
                  specifically   retained  by  the  Audit  Committee  for  such
                  purpose.  You or the authorized legal  representative of your
                  estate  or  the   beneficiaries   thereof  shall  notify  the
                  Executive  Vice  President  and Chief  Financial  Officer  of
                  Celtics,  Inc. in writing of any election to sell  Restricted
                  Units granted  hereunder to BCLP. It is  specifically  agreed
                  that, in determining the price at which any Restricted  Units
                  granted hereunder are to be sold to BCLP:



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                  (1)   The value of such Restricted  Units is to be determined
                        as of the date of the written notice of any election to
                        sell such Restricted Units.

                  (2)   Such Restricted  Units are (x) no longer subject to any
                        of the  restrictions  set  forth  herein;  (y) shall be
                        deemed to be freely  tradable  and not  subject  to any
                        restrictions  with  respect  to  resale  which  may  be
                        imposed by Rule 144  promulgated  under the  Securities
                        Act of 1933, as amended,  or  otherwise;  and (z) shall
                        not  be  subject  to  the  application  of  any  block,
                        blockage or similar discount.

            (b)   For  purposes  hereof,  a  "Change  in  Control"  shall  have
                  occurred if:

                  (1)   any  "Person,"  as such term is used in Sections  13(d)
                        and 14(d) of the  Securities  Exchange Act of 1934,  as
                        amended (the  "Exchange  Act") (other than BCLP and any
                        partnership   or   corporation   owned,   directly   or
                        indirectly,   by  the  security   holders  of  BCLP  in
                        substantially  the same  proportions as their ownership
                        of  securities  of BCLP) is or becomes the  "beneficial
                        owner" (as  defined in Rule  13d-3  under the  Exchange
                        Act),  directly or  indirectly,  of  securities of BCLP
                        representing  50% or more of the combined  voting power
                        of BCLP's then outstanding securities;

                  (2)   the  security  holders  of BCLP  approve  a  merger  or
                        consolidation  of BCLP  with any other  corporation  or
                        partnership,  other than (A) a merger or  consolidation
                        which  would  result in the voting  securities  of BCLP
                        outstanding  immediately  prior  thereto  continuing to
                        represent (either by remaining  outstanding or by being
                        converted  into  voting  securities  of  the  surviving
                        entity) more than 60% of the  combined  voting power of
                        the voting  securities of BCLP or such surviving entity
                        outstanding    immediately   after   such   merger   or
                        consolidation,  (B) a recapitalization or restructuring
                        of BCLP (or any transaction  having a similar  effect),
                        or (C) a merger or consolidation  effected to implement
                        a recapitalization or restructuring of BCLP (or similar
                        transaction); or

                  (3)   the security holders of BCLP approve a plan of complete
                        liquidation  of BCLP or an  agreement  for the  sale or
                        disposition  by  BCLP  of all or  substantially  all of
                        BCLP's  assets  (or any  transaction  having a  similar
                        effect).  In  order  to elect  the  foregoing  exchange
                        option, you must return an executed  counterpart hereof
                        to the  undersigned by telecopy at (617) 720-7833 on or
                        before  July 7, 1997.  If your  signed  election is not
                        received  by the close of  business  on such date,  you
                        will be deemed not to have made an election to make any
                        exchange.



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                                       Very truly yours,


                                       BOSTON CELTICS LIMITED PARTNERSHIP

                                       By: CELTICS, INC., its General Partner


                                       By: /s/ RICHARD G. POND
                                           ------------------------------------
                                           Richard G. Pond
                                             Executive Vice President, 
                                             Chief Financial Officer, Secretary
                                             and Treasurer


AGREED TO AND ACCEPTED ON
THIS 30TH DAY OF JUNE, 1997.
     ----        ----


By: /s/ PAUL E. GASTON
    ------------------------------------
    Paul E. Gaston