SC 13D/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 OMB APPROVAL OMB Number: 3235-0145 Expires: December 31, 2005 Estimated average burden hours per response 11

SCHEDULE 13D

Under the Securities Exchange Act of 1934
(Amendment No. 3)

Centra Software, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

15234X10-3

(CUSIP Number)

Mr. R. Daniel Beckham Criterion Capital Management, LLC 435 Pacific Avenue, 5th Floor San Francisco, CA 94133 415-249-1282 Carolyn S. Reiser, Esq. Shartsis, Friese & Ginsburg LLP One Maritime Plaza, 18^th Floor San Francisco, CA 94111 415-421-6500

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

April 13, 2005

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of sections 240.13d-1(e), 240.13d-1(f) or 140.13d-1(g), check the following box. [ ]

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See section 240.13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only).

Criterion Capital Management, LLC

2. Check the Appropriate Box if a Member of a Group (See Instructions)
(a) X
(b) ______

3. SEC Use Only

4. Source of Funds (See Instructions) AF

5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

6. Citizenship or Place of Organization CA

Number of Shares Beneficially Owned by Each Reporting Person With	7. Sole Voting Power 0
	8. Shared Voting Power 1,736,900
	9. Sole Dispositive Power 0
	10. Shared Dispositive Power 1,736,900

11. Aggregate Amount Beneficially Owned by Each Reporting Person 1,736,900

12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See
Instructions) ______

13. Percent of Class Represented by Amount in Row (11) 6.3%

14. Type of Reporting Person (See Instructions) IA, OO

1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only).

Christopher H. Lord

2. Check the Appropriate Box if a Member of a Group (See Instructions)
(a) X
(b) ______

3. SEC Use Only

4. Source of Funds (See Instructions) AF

5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e) ____

6. Citizenship or Place of Organization USA

Number of Shares Beneficially Owned by Each Reporting Person With	7. Sole Voting Power 0
	8. Shared Voting Power 1,736,900
	9. Sole Dispositive Power 0
	10. Shared Dispositive Power 1,736,900

11. Aggregate Amount Beneficially Owned by Each Reporting Person 1,736,900

12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See
Instructions) ______

13. Percent of Class Represented by Amount in Row (11) 6.3%

14. Type of Reporting Person (See Instructions) HC, IN

Item 1. Security and Issuer

This statement relates to shares of Common Stock (the "Stock") of Centra Software, Inc. (the "Issuer"). The principal executive office of the Issuer is located at 430 Bedford Street, Lexington, MA 02420.

Item 2. Identity and Background

The persons filing this statement and the persons enumerated in Instruction C of Schedule 13D and, where applicable, their respective places of organization, general partners, directors, executive officers and controlling persons, and the information regarding them, are as follows:

(a) Criterion Capital Management, LLC, a California limited liability company ("CCM"), and Christopher H. Lord ("Lord") (collectively, the "Filers").

CCM and Lord disclaim beneficial ownership of the Stock except to the extent of their respective pecuniary interests therein.

(b) The business address of the Filers is 435 Pacific Avenue, 5^th Floor, San Francisco, CA 94133

(c) Present principal occupation or employment of the Filers and the name, principal business and address of any corporation or other organization in which such employment is conducted:

CCM is an investment adviser. Lord is the sole manager and controlling person of CCM. The business address of both is provided in Item 2(b) above.

(d) During the last five years, neither of the Filers has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

(e) During the last five years, neither of the Filers was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f) Please see the cover sheet for each Filer for the citizenship of that Filer.

Item 3. Source and Amount of Funds or Other Consideration

The source and amount of funds used in purchasing the Stock were as follows:

Purchaser	Source of Funds	Amount
Criterion Capital Management, LLC*	Funds under management	$6,331,717

* Purchases were made by CCM on behalf of client accounts.

Item 4. Purpose of Transaction

On January 28, 2005, CCM sent the Nominating and Corporate Governance Committee of the Issuer's Board of Directors a letter. In the letter CCM stated that Evan Marwell, a Managing Director and Senior Securities Analyst of CCM, is interested in joining the Issuer's Board of Directors. A copy of the January 28, 2005, letter is attached to this Schedule as Exhibit B.

On March 29, 2005, counsel for the Issuer sent counsel for CCM a letter stating the Nominating and Governance Committee of the Issuer's Board of Directors had determined not to enlarge the Issuer's Board of Directors to add Mr. Marwell, and that the Committee would again consider Mr. Marwell's request before the Issuer's 2005 annual meeting of stockholders.

On April 1, 2005, CCM sent the Issuer's Corporate Secretary a letter demanding the right, pursuant to Section 220 of the Delaware General Corporation Law, to inspect certain records and documents of the Issuer and to make copies or extracts therefrom. The letter states that the purpose of the demand is to permit CCM to communicate with other stockholders of the Issuer on matters relating to their interests as stockholders, including, but not limited to, and subject to compliance with applicable law, the composition of the Issuer's Board of Directors, the terms of the Issuer's certificate of incorporation and bylaws, and the enhancement of stockholder value. A copy of the April 1, 2005, letter is attached to this Schedule as Exhibit C.

On April 7, 2005, counsel for the Issuer sent CCM a letter stating that the brokerage account statement excerpts attached to CCM's April 1, 2005 letter did not sufficiently identify CCM as the owner of the relevant brokerage accounts.

On April 13, 2005, CCM sent the Issuer's Corporate Secretary a letter demanding the right demanded in its April 1, 2005 letter and attaching additional documentary evidence of CCM's ownership of Common Stock of the Issuer. A copy of the April 13, 2005 letter is attached to this Schedule as Exhibit D.

The Filers acquired the Stock for investment purposes, and such purchases were made in the Filers' ordinary course of business. In pursuing such investment purposes, the Filers may further purchase, hold, vote, trade, dispose or otherwise deal in the Stock at times, and in such manner, as they deem advisable to benefit from changes in market prices of such Stock, changes in the Issuer's operations, business strategy or prospects, or from sale or merger of the Issuer. To evaluate such alternatives, the Filers routinely will monitor the Issuer's operations, prospects, business development, management, competitive and strategic matters, capital structure, and prevailing market conditions, as well as alternative investment opportunities, liquidity requirements of the Filers and other investment considerations. Consistent with their investment research methods and evaluation criteria, the Filers may discuss such matters with management or directors of the Issuer, other shareholders, industry an alysts, existing or potential strategic partners or competitors, investment and financing professionals, sources of credit and other investors. Such factors and discussions may materially affect, and result in, the Filers' modifying their ownership of the Stock, exchanging information with the Issuer pursuant to appropriate confidentiality or similar agreements, proposing changes in the Issuer's operations, governance or capitalization, or in proposing one or more of the other actions described in paragraphs (a) through (j) of Item 4 of Schedule 13D. The Filers reserve the right to formulate other plans and/or make other proposals, and take such actions with respect to their investment in the Issuer, including any or all of the actions set forth in paragraphs (a) through (j) of Item 4 of Schedule 13D, or acquire additional Stock or dispose of all the Stock beneficially owned by them, in public market or privately negotiated transactions. The Filers may at any time reconsider and change their plans or proposa ls relating to the foregoing.

Item 5. Interest in Securities of the Issuer

The beneficial ownership of the Stock by each Filer at the date hereof is reflected on that Filer's cover page.

The Filers effected the following transactions in the Stock in open market transactions on the dates indicated, and such transactions are the only transactions in the Stock by the Filers since 60 days before date on cover page: N/A

Item 6. Contracts, Arrangement, Understandings or Relationships with Respect to Securities of the Issuer

CCM is an investment adviser with discretionary authority over client accounts. Some of CCM's client accounts are limited partnerships for which CCM serves as the general partner pursuant to agreements providing to CCM the authority, among other things, to invest the funds of such partnership in the Stock, to vote and dispose of Stock. Other clients are investment accounts subject to investment advisory agreements providing CCM the authority to invest the assets of the account in the Stock, to vote and dispose of the Stock. Pursuant to such agreements, CCM is entitled to allocations or fees based on assets under management and realized and unrealized gains.

Item 7. Material to Be Filed as Exhibits

Exhibit A. Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G.

Exhibit B. Letter dated January 28, 2005.

Exhibit C. Letter dated April 1, 2005.

Exhibit D. Letter dated April 13, 2005.

SIGNATURES

After reasonable inquiry and to the best of my knowledge, I certify that the information set forth in this statement is true, complete and correct.

Dated: April 14, 2005

CRITERION CAPITAL MANAGEMENT, LLC


By:
Christopher H. Lord, Manager

Christopher H. Lord

EXHIBIT A

AGREEMENT REGARDING JOINT FILING

OF STATEMENT ON SCHEDULE 13D OR 13G

The undersigned agree to file jointly with the Securities and Exchange Commission (the "SEC") any and all statements on Schedule 13D or Schedule 13G (and any amendments or supplements thereto) required under section 13(d) of the Securities Exchange Act of 1934, as amended, in connection with purchases by the undersigned of the common stock of Centra Software, Inc.

Dated: October 12, 2004

CRITERION CAPITAL MANAGEMENT, LLC


By:
Christopher H. Lord, Manager

Christopher H. Lord

EXHIBIT B

LETTER DATED JANUARY 28, 2005

EXHIBIT C

LETTER DATED APRIL 1, 2005

EXHIBIT D

LETTER DATED APRIL 13, 2005

EX-1

January 28, 2005

Centra Software, Inc.
430 Bedford Street
Lexington, Massachusetts 02420
Attention: Nominating and Corporate Governance Committee
of Board of Directors

Ladies and Gentlemen:

I am writing you today to formally express my interest in joining your board of directors at the earliest possible time. The investment fund that I represent, Criterion Capital Management, LLC, is Centra Software's second largest stockholder. Criterion and its affiliates currently hold 1,736,900 shares of Centra Software common stock, representing approximately 6.3% of the company's outstanding common stock. We at Criterion believe that your board of directors would greatly benefit from my participation, particularly due to the significant investment Criterion has made in Centra Software and our commitment to maximizing stockholder value for all of the company's stockholders.

At the request of your counsel, I am submitting this formal request that you consider my appointment to your board of directors in light of the background information attached hereto as Exhibit A. Per your request, I believe that the information set forth on Exhibit A includes all of the material information contemplated by Item 401 of Regulation S-K, but if you believe that I have neglected to provide any information that you require to consider my request, I trust that you will inform me promptly so that I may provide you with the additional information you request as soon as possible. Due to legal requirements of which I am certain you are aware, I am obligated to file this correspondence with the Securities and Exchange Commission and will be doing so promptly.

I am eager to meet with you at your convenience to further discuss my qualifications and my views with respect to Centra Software's future. Kindly contact my counsel to arrange an appropriate time to do so.

I look forward to hearing from you.

Sincerely,

Evan Marwell

cc: Michael S. Ringler, Esq.
Wilson Sonsini Goodrich & Rosati, Professional Corporation

EXHIBIT A

1. Full Legal Name: Evan Chandler Marwell

2. Age and Date of Birth: 39 June 13, 1965

3. There is no arrangement or understanding between me and any other person pursuant to which I am requesting to be selected as a director of Centra Software.

4. I have no family relationship with any director, executive officer or person nominated to be a director or executive officer of Centra Software.

5. I am a Partner and Managing Director of the investment team for Criterion Capital Management, LLC. Before joining Criterion, I was the President and CEO of Quixi, Inc., a venture backed CRM software and services company. Prior to working with Quixi, I was the Founder and President of INFONXX, a global provider of directory assistance services to wireless carriers and Fortune 500 corporations. INFONXX had over 2000 employees and $100MM in revenue. I began my career as a management consultant at Corporate Decisions Inc. (now Mercer consulting) where I was an analyst from 1987-1990. I received my B.A. degree in Economics, cum laude, from Harvard College in 1987 and my M.B.A., with honors, from Harvard Business School in 1992. As you know, none of the foregoing companies are affiliated with Centra Software.

6. I am not currently a member of the board of directors of any corporation.

7. During the past five years, no petition under the federal bankruptcy laws or any state insolvency law has been filed by or against, or a receiver, fiscal agent or similar officer has been appointed by a court, with respect to any company or business association with which I have worked, or any partnership in which I have been a general partner.

8. During the past five years, I have not been convicted in a criminal proceeding or named as the subject of a pending criminal proceeding.

9. During the past five years, I have not been the subject of any order, judgment, or decree, not subsequently reversed, suspended or vacated, of any court permanently or temporarily enjoining me from, or otherwise limiting me from engaging in, any of the following activities:

(a) acting as a futures commission merchant, introducing broker, commodity trading advisor, commodity pool operator, floor broker, leverage transaction merchant, any other person regulated by the Commodity Futures Trading Commission, or an associated person of any of the foregoing, or as an investment adviser, underwriter, broker or dealer in securities, or as an affiliated person, director or employee of any investment company, bank, savings and loan association or insurance company, or engaging in or continuing any conduct or practice in connection with such activity;

(b) engaging in any type of business practice; or

(c) engaging in any activity in connection with the purchase or sale of any security or commodity or in connection with any violation of federal or state securities laws or federal commodities laws.

10. During the past five years, I have not been the subject of any order, judgment or decree, not subsequently reversed, suspended or vacated, of any federal or state authority barring, suspending or otherwise limiting for more than 60 days my right to engage in any activity described above in paragraph 9, or to be associated with persons engaged in any such activity.

11. During the past five years, I have not been found by a court in a civil action or by the Securities and Exchange Commission to have violated any federal or state securities law.

12. During the past five years, I have not been found by a court in a civil action or by the Commodity Futures Trading Commission to have violated any federal commodities law.

EX-2

April 1, 2005

Centra Software, Inc.
430 Bedford Street
Lexington, Massachusetts 02420
Attention: Corporate Secretary

Re: Demand for Right to Inspect Stockholder Information Pursuant to

Section 220 of Delaware General Corporation Law

Ladies and Gentlemen:

Criterion Capital Management, LLC ("Criterion") is the beneficial owner of 1,736,900 shares of common stock ("Common Stock") of Centra Software, Inc. a Delaware corporation (the "Company"). Attached to this letter as Annex A is documentary evidence of Criterion's beneficial ownership of such shares of Common Stock and such documentary evidence is a true and correct copy of what it purports to be.

Pursuant to Section 220 ("Section 220") of the Delaware General Corporate Law, Criterion hereby demands the opportunity to inspect, during the Company's usual hours for business, the following records and documents of the Company and to make copies or extracts therefrom:

1. A complete record or list of the Company's stockholders, certified by its transfer agent and setting forth the name and address of each stockholder of the Company and the number of shares of Common Stock registered in the name of each stockholder of the Company.

2. A magnetic computer tape list of the Company's stockholders, setting forth the name and address of each stockholder and the number of shares of Common Stock registered in the name of each stockholder, together with any computer processing information that may be relevant to the use of such computer tape, and a printout of such magnetic computer tape for verification purposes.

3. All information in or which comes into the Company's possession or control, or which can reasonably be obtained from nominees of any central certificate depository system, concerning the number and identity of the actual beneficial owners of Common Stock, including a list of all owners who hold Common Stock in the name of Cede & Co. or other similar nominees and any respondent bank listings obtained pursuant to the requirements of Rule 14b-2 promulgated under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and a list or lists containing the name, address, and number of shares of Common Stock attributable to participants in any employee stock ownership, incentive, profit sharing, savings, retirement, stock option, stock purchase, restricted stock or other comparable plan of the Company in which the voting of shares held by such plan is made, directly or indirectly, individually or collectively, by participants in such plan.

4. As promptly as practicable, any and all omnibus proxies and correspondent participant listings with respect to all nominees and respondent banks which are currently in effect.

5. All lists, tapes and other data in or which come into the possession or control of the Company, or which can reasonably be obtained pursuant to Rules 14b-1 and 14b-2 promulgated under the Exchange Act, which set forth the name and address of, and the number of shares owned by, each beneficial owner of Common Stock who has not objected to having his or her name disclosed (the "non-objecting beneficial owners" or "NOBO" list).

6. A "stop transfer" list or stop list relating to the shares of Common Stock.

For purposes of the foregoing demand, we request that the Company provide or otherwise make available all such information as of the most recent practicable date and, when available, as of the record date (the "Record Date") for the 2005 annual meeting of stockholders of the Company (the "Annual Meeting"). In addition, we further request that the Company provide or otherwise make available all additions, changes and corrections to any of the requested information from the Record Date until the Annual Meeting. We agree to bear all reasonable costs incurred by the Company in connection with obtaining and furnishing the requested information and other materials.

The purpose of this demand is to permit Criterion to communicate with other stockholders of the Company on matters relating to their interests as stockholders, including, but not limited to, and subject to compliance with applicable law, the composition of the Company's board of directors (including the potential removal of existing directors and election of directors to be nominated by Criterion), the terms of the Company's certificate of incorporation and bylaws, and the enhancement of stockholder value.

Criterion will send an employee to conduct the requested inspection and copying of all requested information and other materials. Please advise the undersigned (Tel: (415) 249-1278) as to the time and place that the requested information will be made available in accordance with this demand. As you are no doubt aware, under Section 220 you are required to respond to this request within five business days of the date of this demand letter.

We trust that this demand letter complies with the provisions of Section 220 in all material respects. If the Company believes this notice is incomplete or otherwise deficient in any respect, however, we request that you contact the undersigned immediately so that any alleged deficiencies may be addressed promptly.

Please acknowledge receipt of this letter and the enclosures by signing and dating the enclosed copy of this letter in the space provided below and returning the same to the undersigned in the enclosed envelope.

Sincerely,

CRITERION CAPITAL MANAGEMENT, LLC

Evan Marwell

Managing Director

cc: Michael S. Ringler, Esq.
Wilson Sonsini Goodrich & Rosati, Professional Corporation

RECEIPT ACKNOWLEDGED:

CENTRA SOFTWARE, INC.

By:__________________

Name:

Title:

Date:

AFFIDAVIT

STATE OF CALIFORNIA

COUNTY OF SAN FRANCISCO

The undersigned, Evan Marwell, being a Managing Director of Criterion Capital Management, LLC, having been duly sworn, hereby declares for and on behalf of Criterion Capital Management, LLC and in its name, under penalty of perjury under the laws of the United States or any state, that the statements and other information set forth in the foregoing stockholder demand letter are true and correct in all material respects as of the date hereof.

CRITERION CAPITAL MANAGEMENT, LLC

Evan Marwell

Managing Director

SWORN TO AND SUBSCRIBED

Before me this 1 day of

April, 2005.

Briana J Curran

NOTARY PUBLIC

ANNEX A

DOCUMENTARY EVIDENCE OF BENEFICIAL OWNERSHIP OF SHARES

EX-3

Criterion Capital Management, LLC
435 Pacific Avenue, 5th Floor
San Francisco, California 94133

April 13, 2005

VIA OVERNIGHT COURIER AND CERTIFIED MAIL

Centra Software, Inc.
430 Bedford Street
Lexington, Massachusetts 02420
Attention: Corporate Secretary

Re: Demand for Right to Inspect Stockholder Information and Corporate Books and Records Pursuant to Section 220 of Delaware General Corporation Law

Dear Sir or Madam:

Criterion Institutional Partners, LP ("Criterion Institutional Partners") is the record holder of' 100 shares of Common Stock ("Common Stock") of Centra Software, Inc. a Delaware corporation (the "Company"). Criterion Institutional Partners' record ownership of the Common Stock is sufficient basis for a demand to inspect the Company's books and records pursuant to Section 220 ("Section 220") of the Delaware General Corporate Law.

We supplementally advise you that Criterion Capital Management, LLC ("Criterion") is the beneficial owner of 1,736,900 shares of Common Stock. Criterion Capital Partners, LP is the beneficial owner of 116,520 shares of Common Stock. Criterion Capital Partners Ltd. is the beneficial owner of 1,076,042 shares of Common Stock. Criterion Institutional Partners is the beneficial owner of 544,338 shares of Common Stock. Criterion is the General Partner of Criterion Institutional Partners, LP and Criterion Capital Partners, LP, and the Investment Advisor of Criterion Capital Partners Ltd. Attached to this letter as Annex A is documentary evidence of Criterion's beneficial ownership of such shares of Common Stock and such documentary evidence is a true and correct copy of what it purports to be. We note that such documentary evidence is not necessary to substantiate the basis for the demand to inspect the Company's books and records.

Pursuant to Section 220, Criterion, on behalf of Criterion Institutional Partners, hereby demands the opportunity to inspect, during the Company's usual hours for business, the following records and documents of the Company and to make copies or extracts therefrom:

1. A complete record or list of the Company's stockholders, certified by its transfer agent and setting forth the name and address of each stockholder of the Company and the number of shares of Common Stock registered in the name of each stockholder of the Company.
2. A magnetic computer tape list of the Company's stockholders, setting forth the name and address of each stockholder and the number of shares of Common Stock registered in the name of each stockholder, together with any computer processing information that may be relevant to the use of such computer tape, and a printout of such magnetic computer tape for verification purposes.
3. All information in or which comes into the Company's possession or control, or which can reasonably be obtained from nominees of any central certificate depository system, concerning the number and identity of the actual beneficial owners of Common Stock, including a list of all owners who hold Common Stock in the name of Cede & Co. or other similar nominees and any respondent bank listings obtained pursuant to the requirements of Rule l4b-2 promulgated under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and a list or lists containing the name, address, and number of shares of Common Stock attributable to participants in any employee stock ownership, incentive, profit sharing, savings, retirement, stock option, stock purchase, restricted stock or other comparable plan of the Company in which the voting, of shares held by such plan is made, directly or indirectly, individually, or collectively, by participants in such plan.
4. As promptly as practicable, any and all omnibus proxies and correspondent participant listings with respect to all nominees and respondent banks which are currently in effect.
5. All lists, tapes and other data in or which come into the possession or control of the Company, or which can reasonably be obtained pursuant to Rules 14b-1 and 14b-2 promulgated under the Exchange Act, which set forth the name and address of, and the number of shares owned by, each beneficial owner of Common Stock who has not objected to having his or her name disclosed (the "non-objecting beneficial owners" or "NOBO" list).
6. A "stop transfer" list or stop list relating to the shares of Common Stock.
7. All minute books of the Company's board of directors and all committees thereof, whether formal or informal, including all written materials distributed to the Company's board of directors and committees in connection with meetings of the board of directors or committees.

For purposes of the foregoing demand, we request that the Company provide or otherwise make available all such information as of the most recent practicable date and, when available, as of the record date (the "Record Date") for the 2005 annual meeting of stockholders of the Company (the "Annual Meeting"). In addition, we further request that the Company provide or otherwise make available all additions, changes and corrections to any of the requested information from the Record Date until the Annual Meeting. We agree to bear all reasonable costs incurred by the Company in connection with obtaining and furnishing the requested information and other materials.

The purpose of this demand is to permit Criterion to communicate with other stockholders of the Company on matters relating to their interests as stockholders, including, but not limited to, and subject to compliance with applicable law, the composition of the Company's board of directors (including the potential removal of existing directors and election of directors to be nominated by Criterion), the terms of the Company's certificate of incorporation and bylaws, and the enhancement of stockholder value.

Criterion will send an employee to conduct the requested inspection and copying of all requested information and other materials. Please advise the undersigned (Tel: (415) 249-1278) as to the time and place that the requested information will be made available in accordance with this demand. As you are no doubt aware, under Section 220 you are required to respond to this request within live business days of the date of this demand letter.

We trust that this demand letter complies with the provisions of Section 220 in all material respects. If the Company believes this notice is incomplete or otherwise deficient in any respect, however, we request that you contact the undersigned immediately so that any alleged deficiencies may be addressed promptly.

Please acknowledge receipt of this letter and the enclosures by signing and dating the enclosed copy of this letter in the space provided below and returning the same to the undersigned in the enclosed envelope.

Sincerely,

CRITERION CAPITAL, MANAGEMENT, LLC

Evan Marwell
Managing Director

cc: Michael S. Ringler, Esq.
Wilson Sonsini Goodrich & Rosati, Professional Corporation

RECEIPT ACKNOWLEDGED:

CENTRA SOFTWARE, INC.

By:

Name:

Title

Date:

AFFIDAVIT

STATE OF CALIFORNIA )

(

COUNTY OF SAN FRANCISCO )

The undersigned, Evan Marwell, being a Managing Director of Criterion Capital Management, LLC, having been duly sworn, hereby declares for and on behalf of Criterion Capital Management, LLC and in its name, under penalty of perjury under the laws of the United States or any state, that the statements and other information set forth in the foregoing stockholder demand letter are true and correct in all material respects as of the date hereof.

CRITERION CAPITAL MANAGEMENT, LLC

Evan Marwell

Managing Director

SWORN TO AND SUBSCRIBED )

)

before me this 13^th day of )

April, 2005.

NOTARY PUBLIC