This book contains a very detailed and thorough account of asana, pranayama, mudra, bandha and kriya and the philosophy and history of yoga.
I would really recommend it for anyone who is looking to develop their yoga practice in a systematic way. The book takes the form of a course which starts from the very beginning opening up the body slowly and in a balanced way and introduces new aspects to the practice in a manageable and structured manner. It takes you from the beginning all the way through to the advanced practices of pranayama and then kriya. There are practice plans in each section, so you can be sure to balance your asanas and these are developed over the course of the book. If you practice according to their instructions you will get a very nice experience of how this type of yoga develops.
The practical lessons have contextual passages as well detailing the history of yoga and the thought behind it.
I would really recommend this to anyone who is looking to commit to more serious yoga practice, who feels confident enough to develop on their own but of course the should have access to a teacher. It is worth noting that in the book they say that the book is intended to act as a teacher and I think it's quite successful at this.
The only thing I would say though is that there is a lot of colorful language and some of the attempts to equate the realizations that come from practice to modern science are not entirely convincing, successful, or necessary. You will also have to be prepared to work through quite alot of text to get to the nub of it all. If you are looking for a concise transmission I would suggest Hatha Yoga Pradipika
. This cuts straight to the point, but leaves the yogi who is not familiar with the practice to do their homework.