I thoroughly enjoyed this book. It is a veritable treasure chest of information, insight, ideas and inspiration for practice, contemplation and just about everything having to do with yoga.
Unlike the previous Feuerstein book I reviewed (The Path of Yoga), this is not an integrated text but rather a collection of essays and musings by the author. Even if you didn't know this, you would quickly suspect it since, while the sections of the book are arranged thematically (general orientation, ethics, practices, etc.), the "chapters" all have a self-contained feel to them. There is also the sense that many were originally part of some larger unit and so when they end they sometimes do so rather abruptly. You're ploughing into the meat of some topic, turn the page, and-wham!-you're on to the next "chapter." This can be a bit jolting, but not all the essays are like this-most have a fully rounded, finished feel to them-but it's often enough that you start expecting/bracing for it. Because the book consists of essays you will also get a fair bit of repetition which, for some people, may be annoying, but for others, who want to drum certain points/facts into their heads, may well be ideal. As for a more in-depth review of the book's contents, with a collection of essays, touching on highlights is the usual approach, and that's what I'll do here.
Clearly Feuerstein has thought a lot about Yoga. As noted, there is something of a"treasure chest" feel to the book; you never know what's up next until you turn the page. And while the vast majority of pieces aim at being informative, many are reflective as well, though only one can be truly called self-revealing. That would be "Crossing the Boundary between Hinduism and Buddhism via Tantra-Yoga," which describes Feuerstein's "conversion" (if that's the right word-probably not) from Hindu yoga to Buddhist yoga (ala Vajrayana). Easily the best of the reflective pieces is #62, "Faith and Surrender: A New Look at the Eightfold Path," a brilliant essay I would heartily recommend for multiple rereadings.
As a scholar though Feuerstein excels at dispensing information. He does this in breadth by touching on just about every conceivable application and type of yoga (I never even knew there was such a thing as buddhi-yoga!), and depth: for example, an eleven page essay on OM reveals this all-important seed mantra's rich textual and cultural legacy. A couple dozen regular volumes might be necessary to cover this much ground and there's no way every topic can be considered in depth; for that you'll have to seek other books. But wait! Dr. Feuerstein has most graciously already considered your predicament and provided an illuminating overview entitled "Introducing the Great Literary Heritage of Hindu Yoga"! An excellent little piece unto itself, an annotated bibliography of books is appended to it, citing quality tomes on general yoga, the Vedas, Brahmanas, Aranyakas, Upanishads, Patanjali, the Epics, Gita, Tantrism and more. All you incurable bibliophiles out there should do three prostrations in Georg's direction. (BTW, he lives in Canada.)
There's very little one can complain about regarding this book. Feuerstein is a writer of clarity and concision, thoughtfulness, depth and sensitivity, not to mention vast knowledge--the man may have read just about everything on the subject. The only, ONLY gripe I might have is a slight tendency-which, frankly, coming from the pen of a scholar is rather ironic-toward a sort of textual fundamentalism. For example, writing on the Mahabharata he repeatedly refers to the war the poem describes as the greatest ever fought on Indian soil and even speaks of "the godman" Krishna as a historical person. This kind of thing comes up more than once-and invariably caused my face to screw up in an incredulous squint-so I have to assume Feuerstein actually believes these things. Suffice to say, I would grant Krishna less historicity than Moses or Lao-tzu, and as for the battle, while I suspect the story has its roots in some historical event(s), I doubt its fidelity to facts in any way exceeds that of the Iliad or the romances of King Arthur.
That being said, buy the book! You won't regret it; Feuerstein's writings will lead you on to richer yogic horizons!