EXHIBIT 5.1
 
                      [LETTERHEAD OF GRAHAM & JAMES LLP]
 
May 7, 1998
 
ATG Inc.
47375 Fremont Boulevard
Fremont, California 94538
 
Ladies and Gentlemen:
 
  We have acted as counsel for ATG Inc., a California corporation (the
"Company"), in connection with the preparation and filing of a registration
statement on Form S-1, Registration No. 333-46107 (the "Registration
Statement"), and a related new registration statement (the "New Registration
Statement") filed pursuant to Rule 462(b) under the Securities Act of 1933, as
amended, with the Securities and Exchange Commission relating to the public
offering by the Company of 1,900,000 shares of its Common Stock, no par value
per share, plus an additional 285,000 shares of such Common Stock to cover
over-allotments, if any (collectively, the "Shares").
 
  In connection with the opinions expressed herein, we have examined the
following documents: (i) the Registration Statement (including exhibits
thereto), as amended through the date hereof; (ii) the New Registration
Statement (including exhibits thereto); (iii) the Articles of Incorporation of
the Company, as amended; (iv) the Bylaws of the Company, as amended; (v) the
minute books of the Company; (vi) the form of Underwriting Agreement to be
executed and delivered by the Company and Van Kasper & Company (the
"Underwriting Agreement"); (vii) the form of Common Stock certificate of the
Company; and (viii) such other documents as we have deemed necessary or
appropriate.
 
  In our examinations, we have assumed the genuineness of all signatures, the
legal capacity of all natural persons, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified, photostatic or facsimile copies and
the authenticity of the originals of such documents.
 
  Based upon our examination of the foregoing documents, and expressly subject
to the assumptions set forth above, it is our opinion that, when issued and
paid for upon the effectiveness of the Registration Statement and the New
Registration Statement and in accordance with the terms of the Underwriting
Agreement and the final Prospectus contained in the Registration Statement,
the Shares will be validly issued, fully paid and non-assessable.
 
  We consent to the filing of this opinion as an exhibit to the New
Registration Statement and to the reference to Graham & James LLP under the
caption "Legal Matters" in the Prospectus incorporated by reference into the
New Registration Statement.
 
                                          Very truly yours,
 
                                          /s/ Graham & James LLP
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                                          GRAHAM & JAMES LLP