EXHIBIT 5.1

                           MORGAN, LEWIS & BOCKIUS LLP
                               1701 MARKET STREET
                      PHILADEPHIA, PENNSYLVANIA 19103-2921


June 27, 2001


Infonautics, Inc.
590 North Gulph Road
King of Prussia, Pennsylvania  19406

Re: Registration Statement on Form S-4

Ladies and Gentlemen:

We have acted as counsel to Infonautics, Inc., a Pennsylvania corporation (the
"Company"), in connection with the Registration Statement on Form S-4 (the
"Registration Statement"), filed by the Company with the Securities and Exchange
Commission pursuant to the Securities Act of 1933, as amended (the "Act"), and
the rules and regulations thereunder, relating to the issuance by the Company of
an aggregate of up to 60,054,111 shares (the "Shares") of the Company's Common
Stock, no par value, pursuant to the Agreement and Plan of Merger (the "Merger
Agreement") by and among the Company, TAC Merger Sub Corporation, a wholly owned
subsidiary of the Company, and Tucows Inc.

We are familiar with the Registration Statement. We have reviewed the Company's
Articles of Incorporation and Bylaws, each as amended to date. We have also
examined corporate records and such other documents, instruments or other
information, and have made such inquiries of the Company's officers, as we
deemed appropriate. In our examination, we have assumed the genuineness of all
signatures, the authenticity of all items submitted to us as originals, and the
conformity with originals of all items submitted to us as conformed, photostatic
or other copies.

Based upon the foregoing, we are of the opinion that the Shares, when issued in
accordance with the Merger Agreement will be validly issued, fully paid and
non-assessable.

We consent to the filing of this opinion as Exhibit 5.1 to the Registration
Statement and to the use of our name in the Prospectus forming a part thereof
under the caption "Legal Matters." In giving such consent, we do not thereby
admit that we are acting within the category of persons whose consent is
required under Section 7 of the Act or the rules and regulations of the
Securities and Exchange Commission thereunder, or Item 509 of Regulation S-K.


Very truly yours,


/s/ MORGAN, LEWIS & BOCKIUS LLP