4.0 out of 5 stars
Well worth buying, stand-alone or as accompliment to the course (cs169.x) but do consider Kindle version for Free upgrades!, 25 April 2014
I did manage to complete the course last year (April 2013) without purchasing this book, however it was a struggle and spent many hours Googling and reading on-line tutorials.
This book gives an excellent background and pre reading for the Engineering Software as a Service CS169.1/2 EDX Course.
The course is being developed continuously, so consider the kindle version, since you can get the upgrades for free (updates and errata fixes).
I would recommend this book, for anyone serious about learning Ruby/rails application development combined with modern practices (Agile, Scrum, Pair programming, Git, Heroku, ...). It's not one book which covers all those topics in detail, you might need to go out and get a Ruby book as well, depending on your experience or whether you can learn languages with online references and materials, but it is the book that brings all those things together into a coherent form in a practical fashion.
Many exercises, and off book references, this, repositories for courseware available for cloning at Github. You learn by doing, and this book will point you n the right direction and give you a good start.