The good folks at Pearson's Addison-Wesley Professional have provided me a copy of Zed Shaw's book to review - that came out in December, Learn Ruby the Hard Way, Third Edition.
I'm enjoying working my way through the book - and particularly liked the subtitle: "A Simple and Idiomatic Introduction to the Imaginative World of Computational Thinking with Code"
The book is __jammed!__ with hands-on exercises (count'em: 52 exercises) - that are brief, direct, succinct - and move the ball constantly forward in terms of raising the readers technical skill with Ruby.
Often a reader will focus solely on the chapters of a book, and ignore the Appendix. That would be a mistake with this book. Zed has provided some very useful exercises to guide the reader through learning the Command Line tools - with a good reinforcing teaching pattern of "Do this...You Learned This...Do more...")
Zed's writing is direct, pragmatic, and focuses on transferring working knowledge of the Ruby language.