(ebook---pdf)-Addison-Wesley---Extreme-Programmin

  First, XP is a programming discipline. We’ll look at a core innovation: how “test-first” changes the programming process itself. We’ll also discuss refactoring, the way XP programmers improve their code. Second, XP is a team discipline. It has evolved a number of practices that help produce a high-performing team. We’ll compare XP to alternative practices, and see some of them in action.