This book is required for the yoga teacher training I am enrolled in. I've read it from cover to cover and I was blown away by the amount of information Coulter presents. He doesn't make references to specific schools but presents things very generally. He also doesn't use too much Sanskrit, so most yoga students shouldn't be too intimidated by the material.
The information he presents on Breathing, the importance of the Abdominopelvic muscles (or the "core muscles", as they're popularly known today) and his chapter on Forward Bends where he discusses nutation were my favorite portions. Coulter isn't doctrinaire in most cases, as is appropriate for someone discussing the anatomical aspect of yoga. He presents variations for the popular poses (forward bends, cobra, triangle, etc.) and discusses what the ramifications of the modifications are. While some are called "advanced" and some are called "beginner", it doesn't come off as a value judgment.
Because Coulter was so thorough throughout the entire book and backed up almost every statement with a logical explanation, it was noticeable when he did not. For instance, he, like almost every other author of a yoga text, recommends that women not practice inversions if they are menstruating. Why? I really hoped that someone with his background would be able to supply an explanation other than because that's the way it's been done. Also, while he spends quite a bit of time talking about the importance of the right tetrahedron for meditation postures and the various postures that can be used, I felt he glossed over the reasons why meditation has to be done sitting versus lying down. Minor quibbles, but only more obvious because the rest of the book is so meticulous.
If you are planning on teaching yoga, if you already have a yoga practice or if you're not quite convinced that yoga can do anything for your body, pick up this book.