I though that it was difficult to read a better book about XP than “Extreme Programming Explained” by Kent Beck. Then, “Extreme Programming Installed” by Ron Jeffries came to me. Last week, I finished it. Ron goes into the detail about the how-to in each XP detail. So, if you want to start with XP, read the explain one, but if you need to go deeper, the installed one is your book.
If you read it, you will get more information about how to do pair programming, what is called the XP circle of life, rights and responsibilities for developers, managers and customers, improve your estimates, when to apply quick design, etc. 5 stars book. I totally recommend it.