This is a decent book, one of the most widely recommended that I've seen around.
The description/definition of social anxiety was good, something that I would probably give to someone else to read to help them understand it.
The "cognitive" part of the book (explanations of different types of negative thoughts and finding alternatives for them, the tables you can photocopy to fill in to help you keep a record of your progress, etc.) was extremely helpful, and I've seen a lot of improvement in myself after trying (and, most importantly, *sticking*!) with the methods used there.
The "behavioural" part and the chapters on building self-confidence and reducing self-consciousness however, were a bit weak and felt rushed, they let the book down, IMHO. Those chapters basically amounted to (respectively) "find something to do and try to be good at it", and "focus on other people instead of yourself". Hmm, useful :|
I think those parts of the book could have benefitted with more "user participation" as per the "cognitive" part of the book - related writing exercises or tables to fill in (for me personally, that kind of thing helps focus my mind on the problem in hand - it was odd that the first part of the book had numerous such things and the second part had maybe *one*), and just more specific exercises in general.
Also, as another reviewer has already mentioned, the dry tone of the book may not be for everyone.