Having bought this book, I will say that it is everything that one could hope for from an instruction manual: informative, lucid and encouraging for the beginner, with plenty of 'easier' options included .
However, I personally find that learning only from a book can be a little dry and uninspiring, and until you can remember the routine you will have to keep resorting back to the page, which can become tiresome when you just want to get on and stretch. And with this in mind, I would like to point out that if you search on the web, you can find David Swenson's DVDs to accompany this book, which will allow you to see everything in the book executed perfectly. Please also remember, whilst Ashtanga-style yoga is very rewarding, it is also challenging; although you can, of course, freely use the postures in this book to put together your own more relaxed Hatha-style workout, if you feel like it. Good luck and good health.