I'm 55 with severe lower back pains, trying to avoid surgery. I've tried 2 different physical therapists and multiple chiropractors, so I've done a fair amount of stretching before reading this book. However, in the first section of this book (through page 18) there were several tips that are priceless (e.g., the difference between Active and Passive stretching; recommending several stretches for warm-ups and several others for cool-down; an analogy with "taffy" illustrating why warm-ups are important). In addition, for the next several pages there is a list of several issues people have (back-pains, hip problems, knee problems, etc), and which exercises are best for people with these problems.
There are 2 issues I've got with the book, which kept me from giving it a perfect 5. First, there is no clear indication of which stretches are "Active" vs "Passive". Second, this book would be as close to perfection as possible if there were icons indicating which exercises were Active, which were Passive, which were particularly recommended for warm-up or cool-down, and which were specifically useful or contra-indicated for people with the various issues such as back-pain, neck problems, hip problems, knee problems, etc.
Even with these 2 issues, I heartily recommend this book for anyone who needs to who is ANY age who wants to start or continue stretching but has the slightest doubts about how to proceed.
I hope the author fixes these 2 issues and either posts the keys on a website or publishes a new version of the book. I know I'd buy it!