Exploring Requirements: Quality Before Design
Gause, Donald C. and Weinberg, Gerald M. Dorset House Publishing Co., Inc. 1989.

The only book on requirements that we know of. Indispensable project management and systems analysis concepts, wonderfully written (an unusual accomplishment for the genre). If you only buy one book this year, make it this one. Guaranteed to make you a better IT professional.

Project Management: A Systems Approach to Planning, Scheduling, and Controlling (6th Edition)
Kerzner, Harold Van Nostrand Reinhold, 1997.

This is the "big book" of project management, and a good choice if you want one comprehensive volume that covers all the bases.

The Mythical Man-Month (Anniversary Edition)
Brooks, Jr., Frederick. Addison-Wesley, 1995.

A classic set of essays on the human element in software project management -- from the school of hard knocks. This 20th (!) anniversary edition contains the author's revisions and reflections. As essential today as it was when first released.

Peopleware : Productive Projects and Teams (2nd Edition)
Demarco, Tom and Lister, Timothy. Dorset House, 1999

New edition! A must for anyone who manages technical people.

Roger C. Parker's Guide to Web Content and Web Design
Parker, Roger. MIS Press, 1997.

Strictly speaking, not a management book, but not a computer book either. However, it's the first book we've found that gets right to the heart of the issue of what the web is all about and provides useful examples of what you should be doing with your own web site. We have no intention of ever becoming HTML hackers, but we do want to use the web to further our business. If this sounds good to you, have a look at this practical, attractive book.