1. Best book on spiritual growth via Yoga philosophy that I have ever read, by far, out of many dozens. I would give it 20 stars if I could. This book is spot on. Brief, to the point, and powerful. No new Age fru fru stuff in here - this is for someone who really wants to start a disciplined spiritual practice that really will lead them somewhere. Amazing. There are many commentaries on the Yoga Sutras that are extremely tedious and long winded. Esp. the ones by Patabi Jois and B.K. Iyengar. Yuck! No wonder so few of their students bother to study Patanjali in depth, lol. THIS commentary is the exact opposite. Easy to read and not at all academic.2. Those of you who still think putting your foot behind your head and holding perfect mula banda makes you an advanced Yogi need to read this book. Yoga has little to do with postures, and Patanjali, the patron saint of Yoga, makes that clear. Patanjali is to Yoga what Lao Tsu is to Taoism. There are only two references to asanas in the entire body of sutras (186 of them) and both of those refer only to a sitting position. Asanas are great, I do them too, but there are many Yogis in India who do none at all; most of the members of the 10 branches of Shankara's ancient monastic order, for example. These are truly the torch bearers of the Yoga tradition, and a several of them are friends of mine from from my many trips there. They are remarkable men (and women!) and I hope to slowly become more like them. This book explains the basics of their philosophy.3. In India, this book is sold by the Ramakrishna Math as "Patanjali Yoga Sutras" by Swami Prabhavananda, and then it mentions Christopher Isherwood as a co-author. So its unclear to me who actually wrote the commentary. If you happen to be going to India, you can probably find it in any of the Ramakrishna Maths scattered over the country.