Exhibit 10.66

               This offer given to Executive on November 30, 2001
                  This offer is valid until December 21, 2001.

             EXECUTIVE SEPARATION, RELEASE AND CONSULTING AGREEMENT

        This Executive Separation, Release and Consulting Agreement (the
"Agreement") is entered into between Ronald R. Barris (the "Executive"), on the
one hand, and Cadence Design Systems, Inc., a Delaware corporation (the
"Company"), on the other hand, as of this 3rd day of December, 2001.

        WHEREAS, the Executive desires to resign his employment as Senior Vice
President, Worldwide Services; and

        WHEREAS, the Executive and the Company desire to reach an agreement
concerning the circumstances under which the Executive's full-time employment
relationship with the Company will terminate; and

        WHEREAS, the Company desires to be relieved of any and all duties,
obligations, and/or liabilities, if any exist, with respect to Executive, other
than those obligations and duties that are expressly stated in herein;

        NOW THEREFORE, in consideration of the foregoing recitals, the mutual
promises contained herein, and for other good and valuable consideration, the
receipt and adequacy of which are hereby acknowledged, the Executive and the
Company agree as follows:

1.      Full-Time Employment.

        Executive will cease his full-time employment as Senior Vice President,
        Worldwide Services of the Company on November 16, 2001, at the close of
        business. All employee benefits, including but not limited to the life,
        dependent life and disability insurance as well as Midwest Legal
        Services will terminate at the end of Executive's full-time employment,
        except that Executive will be eligible to participate in the Employee
        Stock Purchase Plan and 401k contribution through the end of the
        Part-Time Employment Period. Executive's funds invested in the Company's
        Non Qualified Deferred Compensation Plan (the "Plan"), if any, shall be
        treated in accordance with the terms of the Plan.

2.      Part-Time Employment Period.

        a. From November 17, 2001 through November 16, 2002 (the "Part-Time
        Employment Period"), Executive shall be employed by the Company as a
        part-time employee of the Company as Senior Advisor to the President and
        Chief Executive Officer of the Company. Employee's employment with the
        Company shall terminate at the end of the Part-Time Employment Period.
        Executive shall not be eligible to receive any bonus related to his work
        during the Part-Time Employment Period.

        b. During the Part-Time Employment Period, Executive shall be available
        to consult to the Company, and/or the Board of Directors of Cadence as
        necessary. During the


                                        1



        Part-Time Employment Period, Executive shall report to Ray Bingham (or
        his successor(s)) and shall provide general advice and consultation.
        Executive's performance of his duties during this period shall not
        require him to work more than a maximum of twenty (20) hours per week.

        c. In consideration for such employment:

               (i)    Executive shall be paid a monthly salary of $2,000.00,
                      less taxes and standard withholdings required by law to be
                      withheld, and deductions requested by Executive. Such
                      compensation will be paid in accordance with the Company's
                      normal payroll schedule.

               (ii)   Executive shall receive continued vesting during the
                      Part-Time Employment Period of Executive's Company stock
                      options that were previously granted to Executive in
                      accordance with the Stock Option Plan(s) and Stock Option
                      Agreement(s) under which the options granted, so long as
                      Executive has executed all necessary stock option
                      agreements on or before November 16, 2001. Those options
                      will cease vesting at the end of the Part-Time Employment
                      Period, and Executive will have the period of time
                      following his Termination Date that is provided in the
                      applicable stock option agreement(s) to exercise the
                      vested portions, if any.

               (iii)  Executive shall be eligible to participate in the
                      Company's Employee Stock Purchase Plan and 401(k)
                      contribution plan through the end of the Part-Time
                      Employment Period.

               (iv)   Executive shall have certain rights to the real property
                      located at 849 College Avenue, Menlo Park, California as
                      more particularly set forth in Exhibit B attached hereto.

3. In consideration for the covenants and releases given by Executive in this
Agreement (other than his part-time employment), the Company shall provide
Executive with:

        a.     $376,000.00, less taxes and standard withholding required by law
               to be withheld, and deductions requested by Executive, to be paid
               out in twelve equal payments on the fifteenth of each month,
               beginning December 15, 2001; and a bonus in the amount of
               $403,146.23, less taxes and withholdings required by law to be
               withheld, and amounts requested by him to be deducted, including
               (i) $21,855.00, representing the depreciated cost of the Halcon
               Agenda Race Track Desk, Halcon Elliptical Conference Table and
               (5) Harrington leather chairs (which are currently located in
               Executive's former office at the Company's Chelmsford,
               Massachusetts campus and which the Company agrees to move, at the
               Company's cost, to Executive's property located at 8 Winterberry
               Path, Acton, Massachusetts); and (ii) $53,146.23, representing
               the remaining principal and accrued interest (as of February 15,
               2002) due under the promissory note delivered by the Executive to
               the Company dated as of July 15, 2000, on or about February 15,
               2002, so long as


                                        2



               Executive continues in his part-time employment capacity with
               the Company through that date and has not in any way breached
               this Agreement;

        b.     career transition assistance for a period of one year from the
               end of the Part-Time Employment Period provided by a vendor
               chosen by the Company;

        c.     reimbursement for reasonable (as determined by Ron Kirchenbauer)
               costs associated with three trips to Chelmsford, Massachusetts
               for Executive and his wife to be taken by May 30, 2002, provided
               that Executive submits all receipts and appropriate documentation
               to Ron Kirchenbauer by June 15, 2002;

        d.     an audit of Executive's investments in the Telos Venture Plan;

        e.     continuation through December 31, 2001 of Executive's voice
               mailbox and electronic mail address on the Company's systems.

4.      Executive will be free to accept other employment or consulting
        engagements during the Part-Time Employment Period, so long as such
        other employment or consulting engagement does not violate Section 10
        herein.

5.      Executive acknowledges and agrees that except as expressly stated in
        this Agreement he is not entitled to any of the benefits provided in
        that certain offer letter (including attached Employment Terms) dated
        September 7, 1999 or the Cadence Design Systems, Inc. Executive
        Retention Agreement that was entered into on January 17, 2001, and that
        this Agreement supersedes the aforementioned prior agreements and any
        other employment agreements between the parties.

6.      During the Part-Time Employment Period, and following his termination of
        employment, Executive shall fully cooperate with the Company in all
        matters relating to his employment, the winding up of his pending work
        on behalf of the Company and the orderly transfer of any such pending
        work to other employees of the Company as may be designated by the
        Company.

7.      The Executive agrees not to make any statement, written or oral, or
        otherwise engage in any communication that disparages the Company or any
        of the Company's employees, directors, or representatives, products, or
        business practices.

8.      General Release by Executive

                (a) The Executive agrees that the Company has already fully
        satisfied all of its obligations to the Executive arising out of or in
        connection with the Executive's employment including, without
        limitation, all salary, bonuses, accrued vacation, sick pay, and two
        weeks salary as standard termination notice period, and that the
        benefits provided to Executive in this Agreement constitute
        consideration for the covenants and releases of the Executive as set
        forth herein. The Executive acknowledges that the Executive has no
        claims against the Company based on the Executive's employment by the
        Company or the Executive's separation therefrom and irrevocably, fully
        and finally releases the Company, its parent, subsidiaries and
        affiliates, its current and former


                                        3



        directors, officers, agents, attorneys, and employees ("Releasees") from
        all causes of action, claims, suits, demands or other obligations or
        liabilities, whether known or unknown, that Executive ever had, nor now
        has, including but not limited to, any claims that may be alleged to
        arise out of or in connection with the Executive's employment with the
        Company, or separation therefrom, including, not by way of limitation,
        any claims for wages, bonuses, and any claims that any terms of the
        Executive's employment with the Company or any circumstances of the
        Executive's separation were wrongful, in breach of any obligation of the
        Company or in violation of any rights, contractual, statutory or
        otherwise, of the Executive, including but not limited to rights arising
        under Title VII of the Civil Rights Act of 1964, as amended, the
        California Fair Employment and Housing Act, as amended, the California
        Labor Code, the Age Discrimination in Employment Act of 1967, as
        amended, the Americans with Disabilities Act, the Equal Pay Act, the
        Fair Labor Standards Act, as amended, the Employee Retirement Income and
        Security Act of 1974, as amended, (except for Executive's rights under
        COBRA and any right of Executive to the money in Executive's 401(k) plan
        account and/or deferred compensation plan account(s)), and any other
        local, state, or federal law, or law of any country, governing
        discrimination in employment, the payment of wages or benefits, or any
        other aspect of employment (collectively, "Claims").

        IN THIS REGARD THE EXECUTIVE WAIVES ANY RIGHTS CONFERRED BY CALIFORNIA
        CIVIL CODE SECTION 1542 WHICH PROVIDES AS FOLLOWS:

        "A GENERAL RELEASE DOES NOT EXTEND TO CLAIMS WHICH THE CREDITOR DOES NOT
        KNOW OR SUSPECT TO EXIST IN HIS FAVOR WHICH IF KNOWN BY HIM MUST HAVE
        MATERIALLY AFFECTED HIS SETTLEMENT WITH THE DEBTOR."

        (b) The Executive acknowledges that he understands that he may take
        twenty-one (21) days to consider this Agreement and that he has been
        advised that he should consult with an attorney, if he desires to do so,
        prior to executing this Agreement. The Executive further acknowledges
        that he understands that he may revoke this Agreement within seven (7)
        days of his execution of this document and that the consideration to be
        paid to the Executive pursuant to this Agreement will be paid only after
        that seven (7) day revocation period.

9.      Executive acknowledges and incorporates herein by reference his
        continuing obligations under the Employee Proprietary Information and
        Inventions Agreement executed by Executive on September 21, 1999, a copy
        of which is attached hereto as Exhibit A.

10.     As Senior Vice President, World Wide Services and as a Senior Executive
        and Officer of Cadence, Executive has obtained extensive and valuable
        knowledge and information concerning the business of the Company
        (including confidential information relating to the Company and its
        operations, assets, contracts, customers, personnel, plans, marketing
        plans, research and development plans and prospects). The Executive and
        the Company agree that it would be virtually impossible for Executive to
        work as an employee, consultant or advisor to a company in the
        electronic design automation industry without inevitably disclosing
        confidential and proprietary information belonging to the Company.
        Accordingly, the Executive agrees that, during the Part-Time Employment
        Period he will


                                       4



        not, directly or indirectly, provide services on behalf of any competing
        corporation, limited liability company, partnership, or other competing
        entity or person, specifically including but not limited to Avant!
        Corporation, Synopsys Inc., Mentor Graphics Corporation, Simplex
        Solutions, Inc., Magma Design Automation, Inc., or any subsidiary,
        affiliate, division, distributor or partial or complete successor
        thereof, whether as an employee, consultant, independent contractor,
        agent, sole proprietor, partner, joint venture, corporate officer or
        director. For purposes of this Section 10, a "competing" entity is one
        that is engaged in the research, design, development, marketing and/or
        sale of electronic design automation software and related products,
        including products containing hardware, software and both hardware
        and/or software.

11.     Executive agrees that during his employment with the Company, he will
        not, except with the written advance approval of Ron Kirchenbauer (or
        his successor(s)), voluntarily or involuntarily, for any reason
        whatsoever, directly or indirectly, individually or on behalf of persons
        or entities not now parties to this Agreement: (a) encourage, induce,
        attempt to induce, solicit or attempt to solicit for employment,
        contractor or consulting opportunities anyone who is employed at that
        time, or was employed during the previous one (1) year, by the Company
        or any affiliate; or (b) interfere or attempt to interfere with the
        relationship or prospective relationship of the Company or any affiliate
        with any former, present or future client, customer, joint venture
        partner, financial or tax advisor or attorney, or financial backer of
        the Company or any affiliate; or (c) solicit, divert or accept business,
        in any line or area of business engaged in by the Company or any
        affiliate, from any former or present client, customer or joint venture
        partner of the Company or any affiliate (other than on behalf of the
        Company), except that Executive may solicit or accept business, in a
        line of business engaged in by the Company or an affiliate, from a
        former or present client, if and only if Executive had previously
        provided consulting services in such line of business, to such client,
        prior to ever being employed by the Company, but in no event may
        Executive violate Section 10 above. This Section 11, together with
        Section 12, shall supersede paragraph five (5) of the Employee
        Proprietary Information and Inventions Agreement, attached hereto as
        Exhibit A.

12.     During the six (6) months following Executive's employment wit the
        Company, Executive agrees that he will not, except with the written
        advance approval of Ron Kirchenbauer (or his successor(s)), voluntarily
        or involuntarily, for any reason whatsoever, directly or indirectly,
        individually or on behalf of persons or entities not now parties to this
        Agreement: (a) encourage, induce, attempt to induce, solicit or attempt
        to solicit for employment, contractor or consulting opportunities anyone
        who is employed at that time, or was employed during the previous one
        (1) year, by the Company or any affiliate; or (b) interfere or attempt
        to interfere with the relationship or prospective relationship of the
        Company or any affiliate with any former, present or future client,
        customer, joint venture partner, financial or tax advisor or attorney,
        or financial backer of the Company or any affiliate; or (c) solicit,
        divert or accept business, in any line or area of business engaged in by
        the Company or any affiliate, from any former or present client,
        customer or joint venture partner of the Company or any affiliate (other
        than on behalf of the Company), except that Executive may solicit or
        accept business, in a line of business engaged in by the Company or an
        affiliate, from a former or present client, if and only if Executive had
        previously provided consulting services in such line of


                                       5



        business, to such client, prior to ever being employed by the Company.
        This Section 12, together with Section 11 above, shall supersede
        paragraph five (5) of the Employee Proprietary Information and
        Inventions Agreement, attached hereto as Exhibit A.

13.     Notwithstanding the language in Section 22 herein, the parties hereto
        agree that damages would be an inadequate remedy for the Company in the
        event of a breach or threatened breach of Section 10, 11 or 12 of this
        Agreement by Executive, and in the event of any such breach or
        threatened breach, the Company may, either with or without pursuing any
        potential damage remedies, obtain and enforce an injunction prohibiting
        Executive from violating this Agreement and requiring Executive to
        comply with the terms of this Agreement.

14.     Executive represents and acknowledges that the Executive's decision to
        enter into this Agreement has been made voluntarily, knowingly, and
        without coercion of any kind.

15.     Executive represents and warrants that there has been no assignment or
        other transfer of any interest in any Claim, which Executive may have
        against the Releasees.

16.     Executive agrees that if the Executive hereafter commences, joins in, or
        in any manner seeks relief through any suit, claim, demand, charge,
        complaint or otherwise, arising out of, based upon, or relating to any
        of the Claims released hereunder or in any manner asserts against the
        Releasees any of the Claims released hereunder, then the Executive will
        pay to the Releasees, in addition to any other damages caused thereby,
        all reasonable attorneys' fees incurred by the Releasees in defending or
        otherwise responding to said suit or Claim.

17.     Executive acknowledges that he has returned to the Company all copies
        and records of any and all confidential and/or proprietary information
        in his possession or control, as well as all other Company property
        (including but not limited to computers, phones, fax machines, and
        printers) to Ron Kirchenbauer, except as provided for in Section 3.

18.     This Agreement shall be governed and enforced in accordance with the
        laws of the State of California, excluding its conflict of waiver laws
        rules.

19.     In the event that any part of this Agreement is found to be void or
        unenforceable then (a) such provision or part thereof shall, with
        respect to such circumstance and in such jurisdiction, be deemed amended
        to conform to applicable laws so as to be valid and enforceable to the
        fullest possible extent, (b) the invalidity or unenforceability of such
        provision or part thereof under such circumstances and in such
        jurisdiction shall not affect the validity or enforceability of such
        provision or part thereof under any other circumstances or in any other
        jurisdiction, and (c) such invalidity or enforceability of such
        provision or part thereof shall not affect the validity or
        enforceability of the remainder of such provision or the validity or
        enforceability of any other provision of this Agreement as each
        provision is separable from every other provision. If for any reason a
        court of competent jurisdiction or arbitrator finds any provision of
        this Agreement to be unenforceable, the provision shall be deemed
        amended as necessary to conform to applicable laws or regulations, or if
        it cannot be so amended without materially altering


                                       6



        the intention of the parties, the remainder of the Agreement shall
        continue in full force and effect as if the offending provision were not
        contained herein.

20.     Neither party shall, by mere lapse of time, without giving notice or
        taking other action hereunder be deemed to have waived any breach by the
        other party of any of the provisions of this Agreement. Further, the
        waiver by either party of a particular breach of this Agreement by the
        other shall neither be construed as, nor constitute, a continuing waiver
        of such breach or of other breaches by the same or any other provision
        of this Agreement.

21.     The Company shall have the right to assign its rights and obligations
        under this Agreement to an entity that acquires substantially all of the
        assets of the Company. The rights and obligations of the Company under
        this Agreement shall inure to the benefit and shall be binding upon the
        successors and assigns of the Company. Executive shall not have any
        right to assign his obligations under this Agreement and shall only be
        entitled to assign his rights under this Agreement by will or the laws
        of descent and distribution.

22.     The Company and Executive agree that any dispute regarding the
        interpretation or enforcement of this Agreement or any dispute arising
        out of Executive's employment or the termination of that employment with
        the Company, except for disputes regarding the interpretation of those
        section referred to in Section 13 and disputes involving the protection
        of the Company's intellectual property, shall be decided by
        confidential, final and binding arbitration conducted by Judicial
        Arbitration and Mediation Services ("JAMS") under the then-existing JAMS
        rules, rather than by litigation in court, trial by jury, administrative
        proceeding, or in any other forum.

23.     The parties hereto acknowledge that each has read this Agreement,
        understands it, and agrees to be bound by its terms. The parties further
        agree that this Agreement, including the agreements referenced herein
        and attached as Exhibits hereto, constitute the complete and exclusive
        statement of the agreement between the parties and supersedes any and
        all prior or contemporaneous understandings, agreements,
        representations, conditions, covenants, proposals, and all other
        communications between the parties, whether written or oral, relating to
        the subject matter hereof.

24.     Agreement and the terms and conditions of the matters addressed in this
        Agreement may only be amended in writing executed both by the Executive
        and a duly authorized representative of the Company.


                                       7



In witness whereof, the parties hereto have executed this Executive Termination
and Release Agreement, effective eight (8) days after the date it is signed by
both parties below (the "Effective Date").

RONALD R. BARRIS                             CADENCE DESIGN SYSTEMS, INC.

By:   /s/ Ronald R. Barris                   By:  /s/ Ron Kirchenbauer
      --------------------------                  --------------------------
                                                  Ron Kirchenbauer
                                                  Senior Vice President
                                                  Organizational Development

Date: 12/3/01                                Date: 11/30/01


                                       8



                                    EXHIBIT B

                      EXERCISE OF PUT/CALL OPTION AGREEMENT

        This Exercise of Put/Call Option Agreement (this "Exercise Agreement")
is made and entered into as of the 21st day of December, 2001, by and between
RONALD R. BARRIS AND SUSAN E. BARRIS, AS HUSBAND AND WIFE ("Barris") and 849
COLLEGE AVENUE, INC. (the "Company").

                               W I T N E S S E T H

        WHEREAS, Barris and the Company have entered into that certain Put/Call
Option Agreement dated as of September 18, 2000 (the "Option Agreement"); and

        WHEREAS, Barris and the Company desire to confirm Barris' exercise of
the Put Right (as defined in the Option Agreement) as more particularly set
forth herein.

        NOW, THEREFORE, for and in consideration of the premises, the mutual
covenants and agreements herein set forth, and for other good and valuable
consideration, the receipt, adequacy and sufficiency of which are hereby
expressly acknowledged by the parties hereto, the parties hereto do hereby
covenant and agree as follows:

        1. Definitions. All capitalized terms not defined herein shall have the
meanings ascribed thereto in the Option Agreement.

        2. Exercise of Put Option. Barris hereby exercises the Put Right
effective May 30, 2002, and, effective July 1, 2002 ("Listing Date"), agrees to
cooperate with the Company in taking any and all actions the Company deems
necessary to list the Property on the Company's behalf; provided, however, that
notwithstanding the provisions of Section 2 of the Option Agreement regarding
timing of the Closing Date, Barris and the Company hereby agree that the Closing
Date shall be the earlier of (i) 30 days after the Contingency Notice Date, or
(ii) October 31, 2002. As used herein, the "Contingency Notice Date" means the
date on which the Company notifies Barris that all contingencies have been
removed from the contract of sale for the Property; provided, however, that if
such notice is delivered at any time before July 1, 2002, the Contingency Notice
Date shall be deemed to be July 1, 2002.

        3. Possession. On the Closing Date, Barris shall deliver to the Company
possession of the Property in the condition in which Barris occupied the
Property, ordinary wear and tear excepted.

        4. Modifications. Barris shall make no substantial modifications or
improvements to the Property without the prior written consent of the Company.
On the Closing Date, the Company shall pay Barris $47,233.60 to reimburse Barris
for the cost of modifications and/or improvements made prior to the date of this
Exercise Agreement.

        5. Access. From and after the Access Date (as hereinafter defined), the
Company's agents and designees shall have the right, but not the obligation, to
enter upon the Property at


                                       9



all reasonable times after reasonable notice to Barris to examine the condition
of same and to exhibit the Property to the Company's listing agent. As used
herein, the term "Access Date" means the earlier of (i) the date that is fifteen
(15) days before the Listing Date agreed by Barris and the Company pursuant to
Section 2 of this Exercise Agreement, if any, or (ii) June 14, 2002. The listing
agent shall ensure that the Property is locked and that the security system is
armed after showing the Property to potential purchasers.

        6. Insurance. From the date hereof through the Closing Date, Barris
shall keep all buildings and improvements on the Property time insured for the
benefit of the Company and Barris against loss or damage by fire and customary
extended coverage in a minimum amount equal to the full insurable value of such
buildings and improvements. In the event that, at any time before the conveyance
of the Property to the Company on the Closing Date, the buildings and
improvements on the Property shall be destroyed or damaged in whole or in part
by fire or other cause, Barris shall assign to the Company all insurance
proceeds collected in connection with such damage and destruction. Any proceeds
paid directly to Barris shall be held in trust by Barris for the benefit of the
Company and shall be immediately paid over to the Company in accordance with
this Section 6.

        7. Further Assurances. Barris and the Company shall execute and deliver
such further instruments confirming the agreements set forth in this Exercise
Agreement as may be reasonably necessary to effect the purposes set forth
herein, including without limitation a recordable form of this Exercise
Agreement and the documents described in Section 4 of the Option Agreement.

        8. Ratification. The Option Agreement, as modified by this Exercise
Agreement, is hereby ratified and confirmed by Barris and the Company.

        IN WITNESS WHEREOF, the undersigned have caused this Exercise Agreement
to be executed and delivered as of the date first above written.

the "Company":

849 COLLEGE AVENUE, INC.

By:            R.L. Smith McKeithen
   --------------------------------
Name:          R.L. Smith McKeithen
     ------------------------------
Title:         Secretary
      ------------------


"Barris":


/s/ Ronald R. Barris
- -----------------------------------
Ronald R. Barris

/s/ Susan E. Barris
- -----------------------------------
Susan E. Barris


                                       10