XP Series This is a book about Extreme Programming (XP). XP is a lightweight methodology for small-to-medium-sized teams developing software in the face of vague or rapidly changing requirements. This book is intended to help you decide if XP is for you. To some folks, XP seems like just good common sense. So why the iextremei in the name? XP takes commonsense principles and practices to extreme levels. If code reviews are good, weill review code all the time (pair programming). If testing is good, everybody will test all the time (unit testing), even the customers (functional testing). If design is good, weill make it part of everybodyis daily business (refactoring). If simplicity is good, weill always leave the system with the simplest design that supports its current functionality (the simplest thing that could possibly work). If architecture is important, everybody will work defining and refining the architecture all the time (metaphor). If integration testing is important, then...