My thoughts and feelings on this book are mixed, hence the two-star rating. I've been practicing Ashtanga Vinyasa for about 10 years, and I remember when this book initially came out, I was excited to see what it had to offer. Here are my thoughts for now:
What do I like:
(1) Practical tips on how to research certain postures to work on physical problems common to Western students (e.g. tight hips, quadriceps, shoulders, etc).
What I do not like:
(1) The author's use of anatomy to analyze postures is tiresome and oftentimes inaccurate. Maehle does not take into account how muscles and joints function in relation to gravity. It seems as if he has researched what the standard muscular action is based upon a body being in anatomical position, and then he translates that knowledge to whatever position the body is in regardless of its orientation to gravity. For example, he says that the hip flexors pull the spine forward in a seated forward bend (paschimottanasana), which may or may not be the case depending on the relation of the body to gravity. If you are doing a standing forward bend, the hip flexors are usually not concentrically shortening; rather the muscles that are controlling the movement are the eccentric lengthening of the spinal extensors. The same holds true for seated forward bending.
(2) The author has a subtle form of self-promotion in this book. He argues that the Yoga Korunta, the apocryphal text upon which the Ashtanga Vinyasa system is based, was originally bound together with the Yoga Sutras of Patanjali and the Yoga Bhyasa. There is little evidence to support the existence of the Yoga Korunta, much less to support such a combination of the text. It then becomes apparent that the claim only bolsters the author's layout for his own book which combines a verbose and tiresome analysis of ashtanga yoga from an anatomical standpoint (a method which is very antithetical to Guruji Pattabhi Jois's method of 99% practice, 1% theory) with an equally lengthy interpretation of the Yoga Sutra.
If you are interested in a thoughtful approach to Ashtanga Vinyasa Yoga without all of this pseudo-philosophical, pseudo-anatomically-correct coverings, check out Matthew Sweeney's Ashtanga Yoga As It Is, or David Swenson's Ashtanga Yoga: Practice Manual. If you want to read the Yoga Sutras, check out a good thorough translation (Bryant's is notable).
I think this author's book really only get so much good press and high rating because some of the reviews in the book are by the leading teachers of Ashtanga today.