The de facto standard for getting up and running with RoR, from what I've heard. I read the 4th edition. The material was good, but there seemed to be a lot of errors that sent me searching the online errata or on Stack Overflow. Hopefully the later versions have fixed those areas.
One of my first reads about Ruby on Rails, and still the best starting point for anyone new to RoR. The fact that it takes an Agile view is a plus and is what got me interested in Agile development in the first place.
Still one of the best books for beginners to get their heads around a growing framework or for old hands at Rails to get a quick refresh and overview of the new parts of the framework. It's a little light on some parts of Rails development (testing, Rails APIs, etc.) but a solid overview without being over long.
The first half of this book does a nice job of holding your hand and leading you through the creation of an application. Then the authors stick their hands in their pockets and let you fend for yourself. They move from consistent and explained examples to tech shorthand which is the most frequent boo boo of programming books for beginners. I have yet to find the book that speaks English (as opposed to Tech-ese) from cover to cover.
It was one of the books with I read using rapid reading techniques. It means, that my review is going to be biased.
I liked the book - the first part was a hands-on tutorial on building a rails application from stratch. I believe it covered all the most popular issues we have when building web applications. The book includes information on how to do automated testing, like functional and unit testing. However, it expects to enter all commands to the rails console and does not always provide "results" in the book. The second part described implementation details and why Rails works. That part was harded to read rapidly as it contained API descriptions, etc.
I rated this book as 3/5, since for me it would be more appropriate to learn just what API is available. The rest of that I will not memorize anyway, so I will go to the documentation instead, when needed. At the same time, this book gave me a pretty good overview on rails. I recommend reading the first part and skim the second part and get the rest of the knowledge from documentation instead (when needed).