Test-Driven Development: A Practical Guide

This book is a bit outdated (published in 2003, probably written in 2002), but still one of the best practical  examples of what TDD is all about. It talks about unit testing, mocking, integration testing. I am definitely putting this one on my recommended readings list. The part I loved is that the author takes readers from zero to an application implementing not just the back logic, but also the UI, all TDD done. The nice transition from state testing to mocking was very well performed, and in MHO one of the best I have seen so far in books.