Very well written, extremely readable. My only real criticism is the difficulty in using the text as a reference, which in all fairness is not a primary purpose of the author.

Learned RoR using this book as reference

A good introduction to Ruby the language, described coming from the perspective of a Rails user. The chapters on the Ruby environment itself were rather good, if a little too detailed at times. The book was a little long considering what it covered and tried to do too much (i.e. there are better books for learning Rails so it would have been better to shorten those chapters and focus more on the language aspects, tying them back into Rails where appropriate).

gave to chris

Possibly the best computer book I've read for any language.

smart-and-clear, and pedagogically smart.

Best advanced book for Rails programmers to learn advanced Ruby programming techniques. Not a book for beginners.

At times too detailed but great for when I needed the detail I couldn't find anywhere else. What also struck me was that the author is very much a part of the Ruby community and if you want more from him and others all you need to do head out to the rubytalk list.

excellent

highly recommended for anyone new to ruby and rails - this book helped me a ton