Document:

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                                                                   Exhibit 10.15
                                   GUARANTY

     GUARANTY, dated as of April 25, 2000 (as amended or restated from time to
time, this "Guaranty"), by ARTHUR D. LITTLE INTERNATIONAL, INC., a Massachusetts
corporation, and C-QUENTIAL, INC., a Delaware corporation (together with their
successors and assigns, collectively referred to herein as the "Initial
Guarantors" and together with each other entity that becomes a party hereto from
time to time by execution and delivery of a Joinder Agreement, and including
their respective successors and assigns, the "Guarantors"), in favor of each of
the Noteholders (as such term is hereinafter defined).

1.   PRELIMINARY STATEMENT.

     1.1  Arthur D. Little, Inc., a Massachusetts corporation (together with its
successors and assigns, the "Company"), is a party to certain Note Purchase
Agreements, each dated as of December 17, 1996 (collectively, as amended up to
but excluding the date hereof, the "Existing Note Purchase Agreement"), entered
into with each of the institutional investors named on Schedule A thereto,
pursuant to which the Company issued $35,000,000 in aggregate original principal
amount of its 7.16% Senior Notes (the "Existing Notes").  The institutions named
on Annex 1 hereto (together with their respective successors and assigns, the
"Noteholders") were the holders of all of the Existing Notes immediately prior
to the substitution of the Existing Notes for the Notes referred to in clause
(a) of Paragraph 2.1.  Capitalized terms used herein and not otherwise defined
shall have the respective meanings ascribed thereto in that certain Amended and
Restated Note Purchase Agreement, dated as of the date hereof, among the Company
and the Noteholders (the "Amended and Restated Note Purchase Agreement").

     1.2  The Company and the Initial Guarantors have requested the Noteholders
to enter into the Amended and Restated Note Purchase Agreement with the Company
for the purpose of amending certain provisions of the Existing Note Purchase
Agreement and amending and restating the Existing Notes; and in order to induce
the Noteholders to enter into the Amended and Restated Note Purchase Agreement,
each of the Initial Guarantors has agreed to become a Guarantor hereunder and
the Company has agreed, pursuant to the Amended and Restated Note Purchase
Agreement, that each other Person that at any time becomes a Material Subsidiary
(as defined in the Amended and Restated Note Purchase Agreement) will be
required to become a Guarantor hereunder.

     1.3  All acts and proceedings required by law and by the articles of
incorporation and by-laws of the Initial Guarantors necessary to constitute this
Guaranty a valid and binding agreement for the uses and purposes set forth
herein in accordance with its terms have been done and taken, and the execution
and delivery hereof has been in all respects duly authorized by the Initial
Guarantors.
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2.   GUARANTY AND OTHER RIGHTS AND UNDERTAKINGS

     2.1  Guarantied Obligations.
          ----------------------

     The Guarantors, in consideration of the execution and delivery of the
Amended and Restated Note Purchase Agreement by the Noteholders, hereby, jointly
and severally, irrevocably, unconditionally and absolutely guarantee, on a
continuing basis, to each Noteholder, as and for its own debt, until final and
indefeasible payment has been made:

          (a) the due and punctual payment by the Company of the principal of,
     and interest, and the Make Whole Amount (if any) on, the notes issued
     pursuant to the Amended and Restated Note Purchase Agreement (the "Notes")
     at any time outstanding and the due and punctual payment of all other
     amounts payable, and all other indebtedness owing, by the Company to the
     Noteholders under the Amended and Restated Note Purchase Agreement and the
     Notes, in each case when and as the same shall become due and payable,
     whether at maturity, pursuant to mandatory or optional prepayment, by
     acceleration or otherwise, all in accordance with the terms and provisions
     hereof and thereof; it being the intent of the Guarantors that the guaranty
     set forth herein shall be a continuing guaranty of payment and not a
     guaranty of collection; and

          (b) the punctual and faithful performance, keeping, observance, and
     fulfillment by the Company of all duties, agreements, covenants and
     obligations of the Company contained in the Amended and Restated Note
     Purchase Agreement and the Notes.

All of the obligations set forth in clause (a) and clause (b) of this Paragraph
2.1 are referred to herein as the "Guarantied Obligations" and the guaranty
thereof contained herein is referred to herein as this "Unconditional Guaranty"
This Unconditional Guaranty is a primary, original and immediate obligation of
the Guarantors and is an absolute, unconditional, continuing and irrevocable
guaranty of payment and performance and shall remain in full force and effect
until the full and final payment of the Guarantied Obligations.

     2.2  Performance Under the Amended and Restated Note Purchase Agreement.
          ------------------------------------------------------------------

     In the event the Company fails to pay, perform, keep, observe, or fulfill
any Guarantied Obligation in the manner provided in the Notes or in the Amended
and Restated Note Purchase Agreement, the Guarantors shall cause forthwith to be
paid the moneys, or to be performed, kept, observed, or fulfilled each of such
obligations, in respect of which such failure has occurred in accordance with
the terms and provisions of the Amended and Restated Note Purchase Agreement and
the Notes.  In furtherance of the foregoing, if an Event of Default shall exist,
all of the Guarantied Obligations shall, in the manner and subject to the
limitations provided in the Amended and Restated Note Purchase Agreement for the
acceleration of the maturity of the Notes, forthwith become due and payable
without notice, regardless of whether the acceleration of the maturity of the
Notes shall be stayed, enjoined, delayed or otherwise prevented.

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     2.3  Releases.
          --------

     The Guarantors consent and agree that, without any notice whatsoever to or
by it and without impairing, releasing, abating, deferring, suspending,
reducing, terminating or otherwise affecting its obligations hereunder, each
Noteholder, by action or inaction, may:

          (a) compromise or settle, renew or extend the period of duration or
     the time for the payment, or discharge the performance of, or may refuse
     to, or otherwise not, enforce, or may, by action or inaction, release all
     or any one or more parties to, any one or more of this Guaranty, the Notes,
     the Amended and Restated Note Purchase Agreement, any other guaranty or any
     agreement or instrument related thereto or hereto;

          (b) assign, sell or transfer, or otherwise dispose of, any one or more
     of the Notes;

          (c) grant waivers, extensions, consents and other indulgences of any
     kind whatsoever to the Company or any other guarantor in respect of any one
     or more of this Guaranty, the Notes, the Amended and Restated Note Purchase
     Agreement, any other guaranty or any agreement or instrument related
     thereto or hereto;

          (d) amend, modify or supplement in any manner whatsoever and at any
     time (or from time to time) any one or more of the Notes, the Amended and
     Restated Note Purchase Agreement, any other guaranty or any agreement or
     instrument related hereto;

          (e) release or substitute any one or more of the endorsers or
     guarantors of the Guarantied Obligations, whether parties hereto or not;
     and

          (f) sell, exchange, release, surrender or enforce, by action or
     inaction, any property at any time pledged or granted as security in
     respect of the Guarantied Obligations in accordance with the terms and
     conditions of the agreements and instruments pursuant to which such
     property was pledged or granted (as such agreements and instruments may be
     amended from time to time, and without any requirement of notice of such
     amendment to the Guarantors), whether so pledged or granted by the Company,
     the Guarantors or another guarantor of the Company's obligations under the
     Amended and Restated Note Purchase Agreement, the Notes, any other guaranty
     or any agreement or instrument related hereto.

     2.4  Waivers.
          -------

     To the fullest extent permitted by law, the Guarantors do hereby waive:

          (a)  any notice of

               (i) acceptance of this Unconditional Guaranty;

               (ii) any purchase of the Notes under the Amended and Restated
          Note Purchase Agreement, or the creation, existence or acquisition of
          any of the Guarantied Obligations, or the amount of the Guarantied
          Obligations, subject to

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          the Guarantors' right to make inquiry of each Noteholder to ascertain
          the amount of the Guarantied Obligations owing to such Noteholder at
          any reasonable time, provided that the Guarantors will look solely to
          the Company for the determination of the identities of the
          Noteholders;

               (iii)  any transfer of Notes from one holder to another;

               (iv) any adverse change in the financial condition of the Company
          or any other fact that might increase, expand or affect the
          Guarantors' risk hereunder;

               (v) presentment for payment, demand, protest, and notice thereof
          as to the Notes or any other instrument;

               (vi) any Default or Event of Default; and

               (vii)  any kind or nature whatsoever to which the Guarantors
          might otherwise be entitled, other than those specifically required to
          be given to the Guarantors pursuant to the terms of this Guaranty;

          (b) the right by statute or otherwise to require any Noteholder to
     institute suit against the Company, the Guarantors, or any other guarantor
     or to exhaust the rights and remedies of any Noteholder against the Company
     or any other guarantor;

          (c) the benefit of any stay (except in connection with a pending
     appeal), valuation, appraisal, redemption or extension law now or at any
     time hereafter in force which, but for this waiver, might be applicable to
     any sale of property of the Guarantors made under any judgment, order or
     decree based on this Guaranty, and the Guarantors covenant that they will
     not at any time insist upon or plead, or in any manner claim or take the
     benefit or advantage of such law; and

          (d) any defense or objection to the absolute, primary, continuing
     nature, or the validity, enforceability or amount, of this Unconditional
     Guaranty, including, without limitation, any defense based on (and the
     primary, continuing nature, and the validity, enforceability and amount, of
     this Unconditional Guaranty shall be unaffected by), any of the following:

               (i) any change in future conditions;

               (ii)  any change of law;

               (iii)  any invalidity or irregularity with respect to the
          issuance or assumption of any obligations (including, without
          limitation, the Amended and Restated Note Purchase Agreement, the
          Notes or any agreement or instrument related hereto) by the Company or
          any other Person;

               (iv) the execution and delivery of any agreement at any time
          hereafter (including, without limitation, the Amended and Restated
          Note Purchase

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          Agreement, the Notes or any agreement or instrument related hereto) of
          the Company or any other Person;

               (v) the genuineness, validity, regularity or enforceability of
          any of the Guarantied Obligations;

               (vi) any default, failure or delay, willful or otherwise, in the
          performance of any obligations by the Company or any other guarantor;

               (vii)  any creditors' rights, bankruptcy, receivership or other
          insolvency proceeding of the Company, or sequestration or seizure of
          any property of the Company, or any merger, consolidation,
          reorganization, dissolution, liquidation or winding up or change in
          corporate constitution or corporate identity or loss of corporate
          identity of the Company;

               (viii)  any disability or other defense of the Company or the
          Guarantors to payment and performance of all Guarantied Obligations
          other than the defense that the Guarantied Obligations shall have been
          fully and finally performed and indefeasibly paid;

               (ix) the cessation from any cause whatsoever of the liability of
          the Company in respect of the Guarantied Obligations;

               (x) impossibility or illegality of performance on the part of the
          Company under the Amended and Restated Note Purchase Agreement or the
          Notes or of the Guarantors under this Guaranty;

               (xi) any change in the circumstances of the Company, the
          Guarantors or any other Person, whether or not foreseen or
          foreseeable, whether or not imputable to the Company or the
          Guarantors, including, without limitation, impossibility of
          performance through fire, explosion, accident, labor disturbance,
          floods, droughts, embargoes, wars (whether or not declared), civil
          commotions, acts of God or the public enemy, delays or failure of
          suppliers or carriers, inability to obtain materials, economic or
          political conditions, or any, other causes affecting performance, or
          any other force majeure, whether or not beyond the control of the
          Company or the Guarantors and whether or not of the kind hereinbefore
          specified;

               (xii)  any attachment, claim, demand, charge, Lien, order,
          process, encumbrance or any other happening or event or reason,
          similar or dissimilar to the foregoing, or any withholding or
          diminution at the source, by reason of any taxes, assessments,
          expenses, indebtedness, obligations or liabilities of any character,
          foreseen or unforeseen, and whether or not valid, incurred by or
          against any Person, or any claims, demands, charges, Liens or
          encumbrances of any nature, foreseen or unforeseen, incurred by any
          Person, or against any sums payable under the Amended and Restated
          Note Purchase Agreement or the Notes or any agreement or instrument
          related hereto so that such sums would be

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          rendered inadequate or would be unavailable to make the payment as
          herein provided;

               (xiii)  any change in the ownership of the equity securities of
          the Company, the Guarantors or any other Person liable in respect of
          the Notes; or

               (xiv)  any other action, happening, event or reason whatsoever
          that shall delay, interfere with, hinder or prevent, or in any way
          adversely affect, the performance by the Company of any of its
          obligations under the Amended and Restated Note Purchase Agreement or
          the Notes or of the Guarantors under this Guaranty.

     2.5  Certain Waivers of Subrogation, Reimbursement and Indemnity.
          -----------------------------------------------------------

     The Guarantors shall have no right of subrogation, reimbursement, or
indemnity whatsoever in respect of the Guarantied Obligations, and no right of
recourse to or with respect to any assets or property of the Company.

     2.6  Invalid Payments.
          ----------------

     To the extent the Company makes a payment or payments to any Noteholder,
which payment or payments or any part thereof are subsequently invalidated,
declared to be fraudulent or preferential, set aside or required, for any of the
foregoing reasons or for any other reason, to be repaid or paid over to a
custodian, trustee, receiver or any other party or officer under any bankruptcy,
reorganization, arrangement, insolvency, readjustment of debt, dissolution or
liquidation law of any jurisdiction, state or federal law, or any common law or
equitable cause, then to the extent of such payment or repayment, the obligation
or part thereof intended to be satisfied shall be revived and continued in full
force and effect as if said payment had not been made and the Guarantors shall
be primarily liable for such obligation.

     2.7  Marshaling.
          ----------

     Neither any Noteholder nor any Person acting for the benefit of any
Noteholder shall be under any obligation to marshal any assets in favor of the
Guarantors or against or in payment of any or all of the Guarantied Obligations.

     2.8  Subordination.
          -------------

     In the event that, for any reason whatsoever, the Company or a Person
obligated in respect of the Guarantied Obligations pursuant to another
agreement, is now or hereafter becomes indebted to the Guarantors in any manner
(such indebtedness referred to as an "Affiliate Obligation"), the amount of such
Affiliate Obligation, interest thereon, and all other amounts due with respect
thereto, shall, at all times during the existence of a Default or an Event of
Default, be subordinate as to time of payment and in all other respects to all
the Guarantied Obligations, and the Guarantors shall not be entitled to enforce
or receive payment thereof until all sums then due and owing to the Noteholders
in respect of the Guarantied Obligations shall have been paid in full, except
that the Guarantors may enforce (and shall enforce, at the request of the
Required Holders, and at the Guarantors' expense) any obligations in respect of
any such Affiliate

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Obligation owing to the Guarantors from the Company or such indebted Person so
long as all proceeds in respect of any recovery from such enforcement shall be
held by the Guarantors in trust for the benefit of the Noteholders, to be paid
to the Noteholders as promptly as reasonably possible. If any other payment,
other than pursuant to the immediately preceding sentence, shall have been made
to the Guarantors by the Company or such indebted Person on any such Affiliate
Obligation during any time that a Default or an Event of Default exists and
there are Guarantied Obligations outstanding, the Guarantors shall hold in trust
all such payments for the benefit of the Noteholders, to be paid to the
Noteholders as promptly as reasonably possible.

     2.9  Setoff, Counterclaim or Other Deductions.
          ----------------------------------------

     Except as otherwise required by law, each payment by the Guarantors shall
be made without setoff, counterclaim or other deduction.

     2.10  Election by Guarantors to Perform Obligations.
           ---------------------------------------------

     Any election by the Guarantors to pay or otherwise perform any of the
obligations of the Company under the Notes, the Amended and Restated Note
Purchase Agreement or any agreement or instrument related hereto shall not
release the Company, the Guarantors or any other guarantor from such obligations
or any of such Person's other obligations under the Notes, the Amended and
Restated Note Purchase Agreement or any agreement or instrument related hereto.

     2.11  No Election of Remedies by Noteholders.
           --------------------------------------

     To the extent provided in the Amended and Restated Note Purchase Agreement,
each Noteholder shall, individually or collectively, have the right to seek
recourse against the Guarantors to the fullest extent provided for herein for
the Guarantors' obligations under this Guaranty in respect of the Guarantied
Obligations.  No election to proceed in one form of action or proceeding, or
against any party, or on any obligation, shall constitute a waiver of such
Noteholder's right to proceed in any other form of action or proceeding or
against other parties unless such Noteholder has expressly waived such right in
writing.  Specifically, but without limiting the generality of the foregoing, no
action or proceeding by any Noteholder against the Company or the Guarantors
under any document or instrument evidencing obligations of the Company or the
Guarantors to such Noteholder shall serve to diminish the liability of the
Guarantors under this Guaranty, except to the extent that such Noteholder
finally and unconditionally shall have realized payment by such action or
proceeding.

     2.12  Separate Action; Other Enforcement Rights.
           -----------------------------------------

     Each of the rights and remedies granted under this Guaranty to each
Noteholder in respect of the Notes held-by such Noteholder may be exercised by
such Noteholder without notice by such Noteholder to, or the consent of or any
other action by, any other Noteholder.  Each Noteholder may proceed to protect
and enforce this Unconditional Guaranty by suit or suits or proceedings in
equity, at law or in bankruptcy, and whether for the specific performance of any
covenant or agreement contained herein or in execution or aid of any power
herein granted or for the recovery of judgment for the obligations hereby
guarantied or for the enforcement of any other proper, legal or equitable remedy
available under applicable law.

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     2.13  Noteholder Setoff.
           -----------------

     Each Noteholder shall have, to the fullest extent permitted by law and this
Guaranty, a right of set-off against any and all credits and any and all other
property of the Guarantors, now or at any time whatsoever, with or in the
possession of, such Noteholder, or anyone acting for such Noteholder, to ensure
the full performance of any and all obligations of the Guarantors hereunder.

     2.14  Delay or Omission; No Waiver.
           ----------------------------

     No course of dealing on the part of any Noteholder and no delay or failure
on the part of any such Person to exercise any right hereunder shall impair such
right or operate as a waiver of such right or otherwise prejudice such Person's
rights, powers and remedies hereunder.  Every right and remedy given by this
Unconditional Guaranty or by law to any Noteholder may be exercised from time to
time as often as may be deemed expedient by such Person.

     2.15  Restoration of Rights and Remedies.
           ----------------------------------

     If any Noteholder shall have instituted any proceeding to enforce any right
or remedy under this Unconditional Guaranty or under any Note held by such
Noteholder, and such proceeding shall have been dismissed, discontinued or
abandoned for any reason, or shall have been determined adversely to such
Noteholder, then and in every such case each such Noteholder, the Company and
the Guarantors shall, except as may be limited or affected by any determination
(including, without limitation, any determination in connection with any such
dismissal) in such proceeding, be restored severally and respectively to its
respective former positions hereunder and thereunder, and thereafter, subject as
aforesaid, the rights and remedies of such Noteholders shall continue as though
no such proceeding had been instituted.

     2.16  Cumulative Remedies.
           -------------------

     No remedy under this Guaranty, the Note Purchase Agreement or the Notes is
intended to be exclusive of any other remedy, but each and every remedy shall be
cumulative and in addition to any and every other remedy given pursuant to this
Guaranty, the Amended and Restated Note Purchase Agreement or the Notes.

     2.17  Limitation on Guarantied Obligations.
           ------------------------------------

     Notwithstanding anything in Paragraph 2.1 or elsewhere in this Guaranty to
the contrary, the obligations of the Guarantors under this Guaranty shall at
each point in time be limited to an aggregate amount equal to the greatest
amount that would not result in such obligations being subject to avoidance, or
otherwise result in such obligations being unenforceable, at such time under
applicable law (including, without limitation, to the extent, and only to the
extent, applicable to the Guarantors, Section 548 of the Bankruptcy Code of the
United States of America and any comparable provisions of the law of any other
jurisdiction, any capital preservation law of any jurisdiction and any other law
of any jurisdiction that at such time limits the enforceability of the
obligations of the Guarantors under this Guaranty).

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     2.18  Maintenance of Offices.
           ----------------------

     The Guarantors will maintain an office at the address set forth in
Paragraph 5.3(a)(i) where notices, presentations and demands in respect of this
Guaranty may be made upon it.  The Guarantors will maintain their offices at
such address until such time as the Guarantors shall notify the Noteholders of
any change of location of such office.

     2.19  Further Assurances.
           ------------------

     The Guarantors will cooperate with the Noteholders and execute such further
instruments and documents as the Required Holders shall reasonably request to
carry out, to the reasonable satisfaction of the Required Holders, the
transactions contemplated by the Amended and Restated Note Purchase Agreement,
the Notes, this Guaranty and the documents and instruments related thereto.

     2.20  Automatic Release of c-quential, Inc.
           ------------------------------------

     Notwithstanding any other provision of this Guaranty to the contrary, the
obligations of c-quential, Inc. hereunder shall be, without notice of any kind,
automatically and forever released and discharged upon the sale of any shares of
common stock of c-quential, Inc. in an initial public offering pursuant to a
registration statement filed with the Securities and Exchange Commission for the
public offering of shares representing not less than 8% of the common stock of
c-quential, Inc.

3.   INTERPRETATION OF THIS GUARANTY

     3.1  Terms Defined.
          -------------

     As used in this Guaranty, capitalized terms have the meaning specified in
the Amended and Restated Note Purchase Agreement unless otherwise specified
below or set forth in the paragraph of this Guaranty referred to immediately
following such term (such definitions, unless otherwise expressly provided, to
be equally applicable to both the singular and plural forms of the terms
defined):

          Affiliate Obligation -- Paragraph 2.8.

          Amended and Restated Note Purchase Agreement -- Paragraph 1.1.

          Company -- Paragraph 1.1.

          Existing Note Purchase Agreement -- Paragraph 1.1.

          Existing Notes -- Paragraph 1.1.

          Guarantied Obligations -- Paragraph 2.1.

          Guarantors -- has the meaning assigned to such term in the first
paragraph hereof.

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          Guaranty, this -- has the meaning assigned to such term in the first
paragraph hereof.

          Initial Guarantors -- has the meaning assigned to such term in the
first paragraph hereof.

          Joinder Agreement -- Paragraph 5.8.

          Noteholders -- Paragraph 1.1.

          Notes -- Paragraph 2.1.

          Unconditional Guaranty -- Paragraph 2.1.

     3.2  Paragraph Headings and Construction.
          -----------------------------------

          (a) Paragraph Headings, etc.  The titles of the Paragraphs appear as a
              -----------------------
     matter of convenience only, do not constitute a part hereof and shall not
     affect the construction hereof.  The words "herein," "hereof," "hereunder"
     and "hereto" refer to this Guaranty as a whole and not to any particular
     Paragraph or other subdivision.  Unless otherwise specified, references to
     Paragraphs are to Paragraphs of this Guaranty.

          (b) Independent Construction.  Each covenant contained herein shall be
              ------------------------
     construed (absent an express contrary provision herein) as being
     independent of each other covenant contained herein, and compliance with
     any one covenant shall not (absent such an express contrary provision) be
     deemed to excuse compliance with one or more other covenants.

4.  WARRANTIES AND REPRESENTATIONS

     Each Guarantor represents and warrants to each Noteholder, as to itself, as
of the date hereof, as follows:

          (a) Such Guarantor is fully aware of the financial condition of the
     Company and is delivering this Guaranty based solely upon its own
     independent investigation and in no part upon any representation or
     statement of any Noteholder with respect thereto.  Such Guarantor is in a
     position to obtain, and hereby assumes full responsibility for obtaining,
     any additional information concerning the financial condition of the
     Company as such Guarantor may deem material to its obligations hereunder,
     and such Guarantor is not relying upon, nor expecting, any Noteholder to
     furnish it any information concerning the financial condition of the
     Company.

          (b) As of the date of the execution and delivery of this Guaranty,
     there are no presently pending material court or administrative proceedings
     or undischarged judgments against such Guarantor; and no tax Liens have
     been filed or threatened against such Guarantor, nor is such Guarantor in
     default or claimed default under any agreement for borrowed money.

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<PAGE>

          (c) Such Guarantor is a corporation duly organized and validly
     existing and in good standing under the laws of its jurisdiction of
     incorporation. Such Guarantor has the corporate power to own its
     properties and carry on its businesses as they are now being conducted.
     Such Guarantor has the valid authority and the corporate power to enter
     into and perform, and has taken all necessary action to authorize the entry
     into, and the performance and delivery of, this Guaranty and the
     transactions contemplated hereby.

          (d) This Guaranty has been duly authorized by all necessary action on
     the part of such Guarantor, has been duly executed and delivered by one or
     more duly authorized officers of such Guarantor, and constitutes a legal,
     valid and binding obligation of such Guarantor.

          (e) The entry into and performance of this Guaranty and the
     transactions contemplated hereby do not and will not conflict with any
     applicable law or regulation or official or judicial order, conflict with
     the articles of incorporation or by-laws of such Guarantor, conflict with
     any agreement or document to which such Guarantor is a party or that are
     binding upon it or any of its properties, or result in the creation or
     imposition of any Lien on any of its properties pursuant to the provisions
     of any agreement or document.

          (f) Such Guarantor, after giving effect to the transactions
     contemplated by this Guaranty and the Amended and Restated Note Purchase
     Agreement, will not be engaged in any business or transaction, or about to
     engage in any business or transaction, for which it has unreasonably small
     assets or capital (within the meaning of applicable law, including, without
     limitation, Section 548 of the United States Bankruptcy Code), nor does
     such Guarantor have any intent to (i) hinder, delay or defraud any entity
     to which it is, or will become, on or after the date hereof, indebted, or
     (ii) incur debts that would be beyond its ability to pay as they mature.

5.   MISCELLANEOUS

     5.1  Successors and Assigns.
          ----------------------

          (a) Whenever one or more of the Guarantors or any of the parties to
     the Amended and Restated Note Purchase Agreement is referred to, such
     reference shall be deemed to include the successors and assigns of such
     party, and all the covenants, promises and agreements contained in this
     Guaranty by or on behalf of the Guarantors shall bind their successors and
     assigns and shall inure to the benefit of each of the Noteholders from time
     to time whether so expressed or not and whether or not an assignment of the
     rights hereunder shall have been delivered in connection with any
     assignment or other transfer of Notes.

          (b) The Guarantors agree to take such action as may be reasonably
     requested by any Noteholder in connection with the transfer of the Notes of
     such Noteholder in accordance with the requirements of the Amended and
     Restated Note Purchase Agreement in connection with providing an executed
     copy of this Guaranty to the new Noteholder or Noteholders of such Notes,
     provided that no additional obligations of the

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     Guarantors shall thereby be created but rather that its existing
     obligations shall be more particularly stated in respect of one or more
     future Noteholders that are the subject of this Guaranty.

     5.2  Partial Invalidity.
          ------------------

     The unenforceability or invalidity of any provision or provisions hereof
shall not render any other provision or provisions contained herein
unenforceable or invalid.

     5.3  Communications.
          --------------

          (a) Method; Address.  All communications hereunder shall be in
     writing, shall be delivered in the manner required by the Amended and
     Restated Note Purchase Agreement, and shall be addressed:

               (i) if to any Guarantor, c/o Arthur D. Little, Inc., Acorn Park,
          Cambridge, MA 02410-2390, Attention: Chief Financial Officer, Fax:
          (617) 498-7117, or

               (ii) if to a Noteholder, at the address set forth on Schedule A
          to the Amended and Restated Note Purchase Agreement for such
          Noteholder, and further including any parties referred to on such
          Schedule A which are required to receive notices in addition to such
          Noteholder, or to any such party at such other address as such party
          may designate by notice duly given in accordance with this Paragraph
          5.3.

          (b) When Given.  Any communication addressed and delivered as provided
     by Paragraph 5.3(a) shall be deemed to be received when actually delivered
     to the address of the addressee (whether or not delivery is accepted) or
     received by the telecopy machine of the recipient.  Any communication not
     so addressed and delivered shall be ineffective.

     5.4  Governing Law.
          -------------

     THIS GUARANTY IS TO BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH, AND SHALL
BE GOVERNED BY, THE LAWS OF THE STATE OF NEW YORK (WITHOUT GIVING EFFECT TO ANY
LAWS OR RULES RELATING TO CONFLICTS OF LAWS THAT WOULD CAUSE THE APPLICATION OF
THE LAWS OF ANY JURISDICTION OTHER THAN THE STATE OF NEW YORK).

     5.5  Benefits of Guaranty Restricted.
          -------------------------------

     Nothing express or implied in this Guaranty is intended or shall be
construed to give to any Person other than the Guarantors and the Noteholders
any legal or equitable right, remedy or claim under or in respect hereof or any
covenant, condition or provision herein contained; and all such covenants,
conditions and provisions are and shall be held to be for the sole and exclusive
benefit of the Guarantors and the Noteholders.

                                       12
<PAGE>

     5.6  Survival of Representations and Warranties, Entire Agreement.
          ------------------------------------------------------------

     All representations and warranties contained herein or made in writing by
the Guarantors in connection herewith shall survive the execution and delivery
hereof.

     5.7  Expenses.
          --------

          (a) The Guarantors shall pay when billed the reasonable costs and
     expenses (including reasonable attorneys' fees) incurred by the Noteholders
     in connection with the negotiation, preparation or execution of any
     amendments, waivers, consents, standstill agreements and other similar
     agreements with respect hereto (whether or not any such amendments,
     waivers, consents, standstill agreements or other similar agreements are
     executed).

          (b) At any time when any one or more of the Company or the Guarantors
     and the Noteholders are conducting restructuring or workout negotiations in
     respect hereof, or a Default or Event of Default exists, the Guarantors
     shall pay when billed the reasonable costs and expenses (including
     reasonable attorneys' fees and the reasonable fees of professional
     advisors) incurred by the Noteholders in connection with the assessment,
     analysis or enforcement of any rights or remedies that are or may be
     available to the Noteholders.

          (c) If the Guarantors shall fail to pay when due any principal of, or
     Make-Whole Amount or interest on, any Note, the Guarantors shall pay to
     each Noteholder, to the extent permitted by law, such amounts as shall be
     sufficient to cover the costs and expenses, including but not limited to
     reasonable attorneys' fees, incurred by such Noteholder in collecting any
     sums due on the Notes.

     5.8  Joinder Agreement.
          -----------------

     Upon execution and delivery by any entity of a counterpart of a Joinder
Agreement substantially in the form attached to this Guaranty as Annex 2 (each,
a "Joinder Agreement"), this Guaranty shall for all purposes, without further
action, be deemed to have been amended to add such entity as a Guarantor
hereunder with the same effect as if such entity had been an original party
hereto.

     5.9  Amendment.
          ---------

     This Guaranty may be amended only in a writing executed by the Guarantors
and the Required Holders.

     5.10  Survival.
           --------

     So long as the Guarantied Obligations and all payment obligations of the
Guarantors hereunder shall not have been fully and finally performed and paid,
the obligations of the Guarantors hereunder shall survive the transfer and
payment of any Note and the payment in full of all the Notes.

                                       13
<PAGE>

     5.11  Entire Agreement.
           ----------------

     This Guaranty constitutes the final written expression of all of the terms
hereof and is a complete and exclusive statement of those terms.

     5.12  Duplicate Originals, Execution in Counterpart.
           ---------------------------------------------

     Two or more duplicate originals hereof may be signed by the parties, each
of which shall be an original but all of which together shall constitute one and
the same instrument.  This Guaranty may be executed in one or more counterparts
and shall be effective when at least one counterpart shall have been executed by
each party hereto, and each set of counterparts that, collectively, show
execution by each party hereto shall constitute one duplicate original.

     [REMAINDER OF PAGE INTENTIONALLY BLANK.  NEXT PAGE IS SIGNATURE PAGE.]

                                       14
<PAGE>

     IN WITNESS WHEREOF, the Guarantors have caused this Guaranty to be executed
on their behalf by a duly authorized officer.

                              ARTHUR D. LITTLE INTERNATIONAL. INC.

                              By /s/ JOHN F. BURNS
                                 --------------------------------
                                 Name:  John F. Burns
                                 Title: Vice President

                              C-QUENTIAL, INC.

                              By /s/ JOHN F. BURNS
                                 --------------------------------
                                 Name:  John F. Burns
                                 Title: Vice President

                                       15<PAGE>

                                                                   Exhibit 10.16
                                                                   -------------

C-QUENTIAL
--------------------------------------------------------------------------------

                            CONTRACT OF EMPLOYMENT

This Agreement is made on the 26th day of August 2000 between the company c-
quential (hereinafter termed 'the Company') of the one part and Mr. Robert
Broadley of [ENTER ADDRESS] (hereinafter termed 'the Employee') of the other
part.

Now it is hereby agreed as follows:

1.   TERM

     The Employee shall be and is hereby appointed Chief Financial Officer
     (hereinafter termed 'the Position') of the Company c-quential.

     Such employment shall continue for an indefinite period of time unless and
     until this Agreement shall be terminated by not less than 2 months notice
     in writing given by either party to the other.

2.   STARTING DATE

     This appointment will be with effect from a date to be mutually agreed.

3.   PRIOR SERVICE

     No period of service with any previous employer will be regarded as
     continuous with your employment hereunder with the Company.

4.   DUTIES

     The Employee shall, unless prevented by ill health during the continuance
     of this Agreement, devote the whole of his time attention and abilities to
     the business and affairs of the Company.

     In his position, the Employee shall faithfully and diligently serve the
     Company and competently and to the best of his ability carry out such
     duties of whatsoever nature and exercise such powers as are assigned to or
     vested in him by the c-quential CEO for the time being and whether such
     duties and powers are in respect of the Company's own undertaking or
     business or the undertaking or business of any subsidiary or associated
     company of the Company, such subsidiaries or associated companies being
     hereinafter termed 'the related companies'.
<PAGE>

                      c-quential - Contract of Employment                      2
--------------------------------------------------------------------------------

     In the performance of such duties, the Employee shall be responsible to the
     CEO for the time being and shall in all respects conform to and comply with
     such directions and regulations as may be made by the CEO and shall use his
     best endeavours to promote the interests of the Company.

     The Employee's duties and responsibilities will be as detailed in the
     attached Job Description, but this Job Description should not be regarded
     as exclusive or exhaustive. There will be other occasional duties and
     requirements associated with the Employee's appointment and, in addition,
     as a term of his employment, the Employee may be required to undertake
     various other duties as may be reasonably required of him.

5.   COMPENSATION

     The base salary will be at the rate of (Pounds) 140 000 per annum paid in
     twelve equal instalments.

     In addition to this base salary, the Employee will be eligible to an annual
     performance bonus of up to a maximum of 50 % of his base salary, on
     achievement of qualitative and quantitative objectives to be mutually
     agreed between the Employee and the Company.

     The Employee's entitlement to pay during sickness is detailed in the
     attachment.

6.   BONUSES OR GRATUITIES

     Any additional bonus or other gratuity in excess of the total annual
     compensation paid to the Employee (and related payments required by law)
     will be at the sole discretion of the Company and shall not be treated as
     agreed compensation; as such the Company will not be under any obligation
     to repeat such gratuitous payments in subsequent years.

7.   PENSION AND OTHER BENEFITS

     Unless the Employee elects otherwise, he will be enrolled into the Pension
     Plan that benefits to c-quential employees.

     (a)  His life is insured by the Company under its non-contributory Life
     Assurance Plan immediately upon his joining the Company.

     (b)  He will, on the first day of the month co-incident with or immediately
     following his date of commencement with the Company,
<PAGE>

                      c-quential - Contract of Employment                      3
--------------------------------------------------------------------------------

     become a member of the Arthur D. Little Ltd. Pension Investment Plan. The
     rate of contribution and benefits offered under the Plan are set out in the
     explanatory booklet which is enclosed.

     (c)  He will be enrolled into the Company's non-contributory Disability
     Assurance Plan with effect from the first day of the month following his
     date of commencement with the Company.  Under this Plan, he would receive
     benefit in the event of his becoming totally disabled.

8.   PRIVATE PATIENTS' PLAN

     At the present time, the Company is operating under Private Patients' Plan
     a Group scheme to secure certain health care benefits for its employees and
     their immediate dependants under PPP Corporate Health Plan C.  Membership
     of this scheme is optional and the Employee will become eligible to join on
     the first day of the month following his date of commencement with the
     Company.  The Company will bear the full cost of such membership.

     Full details of the Plan will be supplied to the Employee on joining the
     Company.

9.   TRAVEL ACCIDENT INSURANCE

     While travelling on Company business, the Employee will be insured at
     Company expense under an accident insurance policy with a death benefit,
     for the time being, of four times your Standard Compensation, subject to
     minimum and maximum benefits of US $200,000 and $1,000,000 respectively.

10.  TRAVEL AND EXPENSES

     The Company shall provide the Employee with the use of a motor car in
     accordance with the Company's executive car policy for the time being in
     force or a cash alternative of (Pounds) 10, 000 per annum.

     The Company shall reimburse to the Employee all travelling and other
     expenses necessarily incurred by him on behalf of the Company in the proper
     execution of his duties.

11.  SEASON TICKET LOANS

     At the present time, the Company offers a discretionary interest-free loan
     scheme for the purchase of annual season tickets.  The total
<PAGE>

                      c-quential - Contract of Employment                      4
--------------------------------------------------------------------------------

     loan available will be equivalent of one month's salary and repayment will
     be by eleven equal deductions from salary.

     Full details of the scheme will be supplied to the Employee on joining the
     Company.

12.  HOURS OF WORK

     A five-day week is in operation, the basic hours of work being from Monday
     to Friday, 08.45 to17.30, with a break of three-quarters of an hour for
     lunch.

13.  MEDICAL EXAMINATION

     During his employment, the Employee will undergo an annual medical
     examination at the Company's expense and by such Doctor as the Company
     shall nominate and any report of such examination shall be made to the
     Company by such Doctor and shall remain the property of the Company.

14.  HOLIDAYS

     The annual paid holiday will be five weeks (25 working days), raising to
     six weeks (30 working days) with effect from January 2001, to be taken with
     the prior consent of the CEO or his authorised representative.

     Holiday is on a calendar year basis and, for any period of service shorter
     than a year, will be calculated pro-rata.  Each year a portion of this
     leave entitlement is to be taken, at the discretion of the CEO or his
     authorised representative, over the Christmas and New Year period.  The
     normal Bank and public holidays are in addition to the annual leave
     allowance.

     Outstanding holiday entitlement not to exceed 10 days may be carried
     forward from one year to the next with the prior consent of the Managing
     Director or his authorised representative.

     The holiday year runs from 1st January to 31st December in the same year.
<PAGE>

                      c-quential - Contract of Employment                      5
--------------------------------------------------------------------------------

15.  SICK LEAVE

     In the event of an absence due to illness or accidental injury, the
     Employee will be required to notify the Company on the first working day of
     absence. In addition, he should produce or send to the Company a medical
     certificate for any period of absence of seven consecutive days or longer
     (including weekends). He should keep the Company regularly informed each
     week of his medical progress and expected date of return. Further medical
     certificates should be submitted regularly throughout the period of absence
     and a final certificate may be required on recommencing work. Any payment
     due to illness or accidental injury will be entirely at the discretion of
     the Managing Director or his authorised representative. These provisions
     will not affect his right to receive any Statutory Sick Pay (SSP) for which
     the Employee may qualify.

16.  DISCHARGE OF DUTIES

     This appointment will be on a full-time basis, working exclusively for the
     Company.  The Employee's duties will be subject to the direction and
     control of the Company through the CEO or his authorised representative at
     our London office.

     The Employee will be based at the LONDON office, although his work may
     involve visits to other locations both in the U.K. and overseas.

     It is a condition of this employment with the Company that the Employee
     will comply with the Company's code on Ethics, Conduct and Conflict of
     Interest, a copy of which will be provided upon joining and is available
     for prior review from the personnel office.

17.  SECRECY

     The Employee shall not either during the currency of this Agreement or
     thereafter without the consent of the CEO being first obtained divulge to
     any person whatsoever or use for the benefit of anyone other than the
     Company or its related companies any secrets of the Company or any
     confidential research information and design techniques of a confidential
     nature or any confidential information concerning the business accounts or
     finance of the Company or its related companies or any of its or their
     transactions or affairs which may have come to his knowledge during the
     course of his service with the Company or with any such related as
     aforesaid. And in addition the Employee shall use his best endeavours to
     prevent the publication or disclosure of any such secrets research
     information design techniques or information as aforesaid.
<PAGE>

                      c-quential - Contract of Employment                      6
--------------------------------------------------------------------------------

     All records and documents made by the Employee or in his possession
     relating to the matters aforesaid shall be and remain the property of the
     Company or of its related companies as the case may be and the Employee
     shall hand the same over to the Company at any time on demand and in any
     event on the termination of his employment.

18.  INVENTIONS

     If the Employee shall during the continuance of this Agreement invent or
     discover any process or invention relating to the businesses of the Company
     or its related companies or become possessed of any such invention or
     discovery it shall become the property of the Company and the Employee at
     the request and expense of the Company shall do all acts and things
     necessary for obtaining a patent or patents for the same if patentable or
     otherwise making the same available to the Company.

19.  NON-SOLICITATION

(a)  Upon the termination of his employment for whatever reason, the Employee
     shall not as principle servant or agent:

     (i)  for a period of one year from the date of such termination, solicit in
          competition with the Company or any of its related companies the
          custom of any person firm company or organisation who at any time
          during the 12 months ending upon the date of such termination shall
          have been a customer of the Company or any of its related companies;

     (ii) for a period of one year from the date of such termination in
          competition with any associated company of the Company, solicit the
          custom of any person firm company or organisation who at any time
          during the 12 months ending upon the date of such termination shall
          have been a customer of such related company and shall have been a
          customer with whom the Employee shall have been in contact in respect
          of such service in the performance of his duties at any time during
          the said period 12 months ending upon the date of such termination.

(b)  The Employee hereby agrees that he will not after the termination of his
     employment either personally or by his agent directly or indirectly:

     (i)  at any time represent himself as being in any way connected with or
          interested in the business of the Company or the business of any of
          its related companies;
<PAGE>

                      c-quential - Contract of Employment                      7
--------------------------------------------------------------------------------

     (ii)  at any time use or disclose to any person firm company or
           organisation any confidential information directly relating to the
           affairs of the Company or any of its related companies or of any
           customer of the Company or of any such related company which may have
           been acquired by him in the course of or incidental to his employment
           by the Company or by any of its related companies or of any such
           customer as aforesaid;

     (iii) for a period of 12 months after the termination of his employment
           either on his own account or for any other person, firm, company or
           organisation solicit interfere with or endeavour to entice away from
           the Company or from any of its related companies any employee of the
           Company or any employee of its related companies as aforesaid.

20.  OTHER EMPLOYMENT

     During the continuance of this Agreement the Employee shall not without the
     consent of the CEO directly or indirectly be engaged concerned or
     interested in any other business or occupation whatsoever either alone or
     jointly with or as a Director, Manager, Agent or Employee of any person
     firm company or organisation.

21.  TERMINATION

     The appointment will be terminable by two months' notice by either party or
     such statutory minimum period of notice as is required under the law in
     force at the date of termination, whichever is the greater, or as otherwise
     mutually agreed.

     Full details of the minimum periods of notice in operation at any time may
     be obtained on request from the Company Secretary or his authorised
     representative.

22.  CANCELLATION OF PREVIOUS AGREEMENT

     This Agreement is in substitution for and supersedes all previous contracts
     of service and arrangements whether written, oral or implied between the
     Company and the Employee relating to the service of the Employee or between
     the Employee and any related company all which Agreements and arrangements
     shall be deemed to have been terminated by mutual consent as from the
     Commencement Date.
<PAGE>

                      c-quential - Contract of Employment                      8
--------------------------------------------------------------------------------

23.  ARBITRATION

     If he has any grievance or complaint concerning his employment with the
     Company, the Employee is invited to raise the matter with the Company Human
     Resources Director either orally or in writing, whose decision on the
     matter shall be final.

24.  INTERPRETATION

     In this Agreement, the following expressions shall have the meanings
     assigned to them herein:

(a)  'Subsidiary': Any company which for the time being is a subsidiary of the
     Company as defined by the Companies Act as amended for the time being in
     force;

(b)  'Associated Company': Any company which for the time being is a holding
     company as such expression is defined by the Companies Act as amended for
     the time being in force or any subsidiary of any such holding company.

25.  LAW

     This Agreement shall be subject to the law of United Kingdom.

26.  OTHER ASPECTS OF EMPLOYMENT

     All other aspects of the Employee's employment with the Company not herein
     covered shall be dealt with in accordance with the Company's policies, or,
     failing a policy in the matter in accordance with English common law.

27.  MISCELLANEOUS

     No provisions of this Agreement may be modified, waived or discharged
     unless such waiver, modification or discharge is agreed to in writing
     signed by the Employee and the Company.
<PAGE>

                      c-quential - Contract of Employment                      9
--------------------------------------------------------------------------------

28.  AGREEMENT

     If you are willing to accept the terms of this contract, please sign and
     date this document below. Please retain one copy and return the other to
     Personnel at the Company's address.

--------------------------------------------------------------------------------
            The Employee                                 The Company
--------------------------------------------------------------------------------
I acknowledge receipt of a copy of the above,     Name :
and hereby agree to the terms and particulars
of my employment as detailed therein.
                                                 -------------------------------
                                                  Position :
--------------------------------------------------------------------------------
Date :                                            Date :

--------------------------------------------------------------------------------
Signature :                                       Signature :

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

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