I can't fault it. It's comprehensive and user friendly. This is an aspect of physical training that's often over-looked, but a good grounding in this is important if you want to avoid injury and develop your overall conditioning - especially as you get older.
I've had alot of bad advice -some of it resulting in injury- over the years, as I'm sure many people have on this topic. This book gives you all the basics, good advice, as many exercises as you will ever need, has answered all my concerns and corrected all my bad habits; such as, the important distinction between light, aerobic type stretches for warming up, and deeper, progressive stretches after the muscles are well warmed. This book divides the two simply.
I've also been surprised at how stress-reducing and pleasurable a regular routine can be - unkinking knots and improving circulation.
I'll be referring to this for many years to come.