Exhibit 5.1

                               EXHIBITS 5.1 & 23.3

   
January __, 1998
    

Interleaf, Inc.
62 Fourth Avenue
Waltham, MA 02154


Gentlemen:

   
I have assisted in the preparation of a registration statement on Form S-3 to be
filed with the Securities and Exchange Commission (the "registration
statement"), relating to 1,761,167 shares of common stock, $.01 par value per
share (the "Shares"), of Interleaf, Inc., a Massachusetts corporation (the
"Company"), pursuant to the several common stock Purchase Agreements between
Interleaf and each of certain accredited investors dated as of November 18, 1998
(collectively, the "Agreement").
    
   
I have examined (i) the Restated Articles of Organization and By-laws of
Interleaf and all amendments thereto, (ii) the Agreement, and (iii) such records
of meetings of the directors and stockholders of the company, documents and
other instruments as in my judgment are necessary or appropriate to enable me to
render the opinion expressed below.
    

In my examination of the foregoing documents, I have assumed the genuineness of
all signatures and the authenticity of all documents submitted to me as
originals, the conformity to original documents of all documents submitted to me
as certified or photostatic copies, and the authenticity of the originals of
such latter documents.

Based upon the foregoing, I am of the opinion that the Shares have been duly
authorized for issuance and, when issued pursuant to the terms of the Agreement,
will be legally issued, fully paid and nonassessable.

I hereby consent to the use of my name in the registration statement and consent
to the filing of this opinion with the Securities and exchange Commission as an
exhibit to the registration statement.

Very truly yours,


   /S/  CRAIG NEWFIELD                      
- ----------------------
Craig Newfield,
General Counsel