I didn't read this book cover to cover. It's a decent reference that I'll return to when I need it.
While there's a lot of good info here, this is by no means a replacement for medical advice! I found the most useful chapters to be on the importance of warming up for injury prevention, general mental attitude/fortitude and approaches to climbing, and how to cope with injury from a psychological perspective. Many of the exercises provided are fairly basic so anyone with chronic or serious injuries should definitely seek out the help of sports medicine professionals. In my opinion, it's not enough to go to any orthopedic doctor or physio - you need to find someone who understands the unique needs of climbing/bouldering and who understands your goals specific to the sport.
Overall, I think this is a great book for climbing newbs, but if you've been in it for a while and are already nursing chronic injuries or even just niggles, you will probably be doing a lot of nodding and saying 'tell me something I don't know' while reading this. As I mentioned already, the chapters dealing with the psychological aspects of injury recovery were definitely the most helpful to me.