Rating: 

When I chose this book, I was expecting the quick, pithy introduction to the subject that I am used to from the many OReilly books that I have read and profited from in the past.

However this book makes a number of critical mistakes.

It is far too closely tied to the example application that is developed throughout its course. I want to learn XUL and firefox, as advertised on the cover.
I shouldn't need to understand and install PHP, Apache and MySql in order to get the sample application up and running. In any case, the hasty explanations of these peripheral technologies whould not,IMHO, have been enough to get the uninitiated up and running.

In the text there is way too much code listing which makes it very hard to follow and rather a tedious read.

Worst of all, the code samples on the web-site are extaordinarily skimpy. I'm used to being able to spend a couple of hours reading the first few chapters of an OReilly book, then using the sample code as a quick-start to building my own apps. It was was not possible with this book. I read up to the end of chapter 6 then downloaded the source code hoping to quickly run it and adapt it to my own usage. However there was no useful relationship between the chapter content and the content in the example source code.

Unfortunately I really feel like the time I spend reading the book has been wasted. I hope that readers new to OReilly will understand that this is not up to their usual world-beating standard.