I got the early release of this book on Oreily Safari and I have a rather low opinion of this book. I was developing a Backbone.js app wanted to use this book to provide insights but this book was surprisingly completely unhelpful. I was ( and I guess I still am )struggling with rendering components , item views and list views and managing events/models and struggling with router etc. I am not the only programmer with these issues; there are plenty of non-trivial question about backbone.js on Stackoverflow. This book has little to help one understand the internals of backbone.js or how and where to apply underscore.js . For some reason this book veers off into node.js development as if every one using backbone.js is going to wrote a node.js back-end server app. Thankfully enough, there are several outstanding tutorials on the web on backbone.js and the underscore.js libraries as very well documented and the demo app is also very illustrative. I purchased this book on OReilly Safari to support the authors but the book is a complete disappointment.