There are too many weak points of this book. Let's mention some of them:
- its english is simply incompetent and unsufficient for this kind of book - instead of a patterns catalogue, this book offers some examples of basic usage of main backbone elements. No original ideas, no creativity at all. Therefore is quite useless for regular advanced users. - it lacks basic introduction of backbone concepts and that makes it totally useless for beginners - it contains some OBVIOUS errors, especially in code snippets, meaning it was not even once tested - It is swamped by statements like this "that's not the best approach", "this is a typicall error", "this can cause problems", surprisengly not revealing alternative approaches, thus leaving readers confused and with open questions - examples are just badly conceptualised - incompletelly printed, refering to information that is not even there (e.g. "the resulting output of this example is the same as in the previous case", with previous case's output not present??!). This makes downloading examples mandatory and reading book in offline mode practically impossible (I would never buy it knowing this) - coding style itself is pretty weak and making a bad example
This is simply a bad book, misleading for newbies and useless for the others, I see no target reader. Shame for the editor.
The author writes that this book requires some basic knowledge of Backbone.js - well, i would say that he is correct. You do need to understand the basic concepts, but i'd definitely suggest it to anyone who is working with Backbone and you don't need to be very experienced.
The book is not just about Patterns and Best Practices, the first half of it is more like a reference for Models, Views and Controllers. Which is good, because you don't need an extra book for that and it helped me a lot as Backbone beginner. Skip the first half of the book if you feel like a pro in Backbone, but don't miss the second half because that's where you get a deep knowledge of how you should structure your apps, including Require.js and AMD modules. You don't see separate recipe after recipe, which is good because every chapter fits together very well and explains all important aspects of Backbone.
So this is definitely worth to buy if you are interested in working with Backbone.js. Only Chapter 8 about unit testing is a bit too short in my opinion and i would have liked to see some testig with more professional frameworks like Jasmine or Mocha. But that's more of a personal taste.