The Pragmatic Programmer: from Journeyman to Master
By Andrew Hunt and David Thomas
A down-to-earth attitude for all programmers.

Software Craftsmanship: The New Imperative
By Pete McBreen
A wonderful description of the software trade. A must read for every software professional.

Essential COM
By Don Box (1997)
The first chapter of this book is one of the most lucid explanations of COM that I have ever seen. After reading it, you will understand what COM wants to be. The remaining chapters do a good job of telling you what COM is.

Controlling Software Projects
By Tom DeMarco (1986)
"You can't manage what you can't control; and you can't control what you don't measure." This is one of the most important books that a software manager or technical lead can read. It neatly defines ways of measuring, and thereby controlling the process of software development. Outstanding!