If you want to learn the principles of XP, this is THE book. If you want to learn the practice of XP, there are better alternatives.
The ideas and motivation of XP are explained clearly and concisely. It's a short read, but fairly convincing. However, if you learn better from examples, this book does not have enough real world stories to really see XP in action.
The book is full of great quotes:
XP is a lightweight methodology for small-to-medium-sized teams developing software in the face of vague or rapidly changing requirements.
Everything in software changes. The requirements change. The design changes. The business changes. The technology changes. The team changes. The team members change. The problem isn't change, because change is going to happen; the problem, rather, is our inability to cope with change.
No book of gardening, however complete, makes you a gardener. First you have to garden, then join the community of gardeners, then teach others to garden. Then you are a garden
As Will Rogers said, “It ain't what you don't know that gets you in trouble. It's what you know that ain't so.”
If members of a team don't care about each other and what they are doing, XP won't work. If members of a team don't care about a project, nothing can save it.
In software development, “perfect” is a verb, not an adjective.
Quality isn't a purely economic factor. People need to do work they are proud of.
Automatically build the whole system and run all of the tests in ten minutes. A build that takes longer than ten minutes will be used much less often, missing the opportunity for feedback. A shorter build doesn't give you time to drink your coffee.
Put new software into production every night. Any gap between what is on a programmer's desk and what is in production is a risk. A programmer out of sync with the deployed software risks making decisions without getting accurate feedback about those decisions.
Silence is the sound of risk piling up.
He picked a powerful metaphor for his teaching, Scientific Management. When picking descriptive names, it helps to pick a name whose opposite is unappealing. Who could possibly be for “unscientific” management?
Having a separate quality department sends the message that quality is exactly as important to engineering as marketing or sales. No one in engineering is responsible for quality.