Real-Time Collision Detection (The Morgan Kaufmann Series in Interactive 3-D Technology)

Even though I got this book from another source other than Amazon, I believe it's worth noting that this book is excellent. It is thorough from theory to implementation. It not only contains the theory necessary to implement your own libraries but also tips and secrets one learns by actually coding them --with the advantage the author hands them to us. Probably this one is to physics/collision detection as Real-Time Rendering, Third Edition is to rendering/computer graphics in general. The book is an excellent reference and I always have it close to me.