The Mythical Man Month - Frederick P Brooks
This is a must have book for software developers. Most software development tomes talk about coding software, programming languages and the latest technologies and techniques to write software.
In "The Mythical Man Month" - Mr. Brooks tackles a more fundamental (IMO) aspect of software development - the social aspect. He addresses the problems faced in a major software project, from the problem of adding people, the second system effect, and the need for proper process.
This books is one that looks at programming from the perspective of making it an engineering discipline, something that can be used to engineer a large, complex piece of software.