"Open Sources" is a comprehensive and topical collection of beautiful
essays. You won't find more relevant information or as many thoughtful
opinions on this movement in one place. It may sound repetitive if you've
been following free software for years, but the reference value compensates.
And Appendix A (the famous "Linux is obsolete" debate) is a worthwhile
companion for any Linux (or Linus) fan.

However, I was disappointed in the care that O'Reilly gave to the production
of such an important handbook. The many typographical errors suggest that
it was edited hastily. Worse, the Introduction by DiBona, Ockman and Stone
is fraught with inaccuracies and appears positively meretricious before the
wonderful and insightful pieces that follow.