Creativity, Inc.
This is one of the best web design books I've ever read. And it's not a web design book. This book is a treasure trove of insights and lessons learned from Pixar, which very much apply to running a web development business and working with different teams and company cultures. So much of this book resonated closely with me, especially the notion of getting out of the way and letting smart people solve problems and do their jobs rather than trying to over manage them. If you make money doing creative work and work with other people, this book is for you.