When the PC struck in 1981, software scarcely dribbled into most offices. Now there's an unstemmable torrent. As documentation, the 14th edition of The Corporate Software Guide (800-677-4000; $135) is 25% thicker than the previous edition. The almost 1,400-page tome describes nearly every Mac and IBM program a modest-size business might find useful. The catch is that it's also a sales catalog for its publisher, a software distributor. But the company claims that products have been reviewed by technicians who are free to append adverse comments. More objective, more detailed, and more expensive is "Software Digest Ratings Newsletter" (800-223-7093; $445 for 15 IBM issues; $185 for 12 Mac issues), which runs each product mentioned through exhaustive tests and assigns a relative overall score. -- Robert A. Mamis

* * *