There are two things to be said about the Dojo Javascript Toolkit:

1) Is is a very ( if not the most) complete Javascipt framework out there.
2) It is poorly ( if not the poorest ) documented framework out there.

Dojo has always had one major drawback;  it's documentation (the achilles heel of many open source projects).  Admittedly, things have improved seriously over the last year or so, but still I was waiting eagerly for a book on the subject.

So I was happy to finally see one or two books being published recently and  I got myself a copy of  Dojo: The Definitive Guide. by Matthew A. Russell.

This book makes Dojo a lot better to grasp and Matthew A. Russell (as far as I can tell not related to Alex Russell, the founder of Dojo and president of the Dojo Foundation) structured the book in a way that presents the Dojo framework  in a clear and concise way.

The downside to this book however are the many, many errors. Not even taking the typo's and wrong references into consideration, the worst errors are the ones made in the coding examples.
It is very apparent O'Reilly didn't spent much time on reviewing the book before it got printed. Due to these errors I can only really recommend this book to those who are experienced Javascript programmers who can immediately see the flaws in the examples.

Conclusion: Great for experienced Javascripters who can live with the book's flaws.

Update:  If you want to have a good laugh, read this review on  the book at about.com. The reviewer, Stephen Chapmann is clearly totally clueless.
So much for the credibility of about.com.