I've only been using this book for a few days and already run into serious problems.
Firstly, although I suspect it contains most, if not all, the information you need to get the most out of Wordpress, it's very badly organised, and not brilliantly written. To take just one example: the description of what a 'child theme' is (page 537) is nowhere near as concise and easy to understand as the definition of a child theme on the Wordpress website itself. If a book like this isn't at least as easy to grasp as the information on the product website, then it isn't doing its job properly.
Secondly, and much more seriously, I've come across significant errors. For example, in the section 'Putting It All Together' starting on page 508, instructions are given on creating a simple theme. All you need to do is copy the code and upload it to your server. This should be completely straightforward. Except that the code contains numerous mistakes. You can see this clearly by comparing the individual lines of code for the index.php file with the summary of the completed code on page 515: they should be the same, but they aren't, as you will find when you try to use it. I spent an hour debugging before I could get it to work. This is just not acceptable.