Backbone.js is known for its excellent documentation. I would suggest going through their examples first. The tutorials range from beginner to intermediate. The ToDo application is easy enough to understand and I believe and excellent resource to help you grasp backbone.js.

Besides the official documentation I recommend you check out this screencast from Joey…
Another resource for beginners would be the tutorials found here:

I don’t think that one book or tutorial would be enough to learn Backbone.js. Here’s a list of all the resources I used to learn it:

Official Documentation

The Backbone.js and Underscore.js docs are extremely well written and organized. I like to keep them open in a tab when developing.

Collections of Tips, Techniques, etc.


Blog Posts

Other Collections of Resources