When I first started doing yoga, I had taken only one class and learned a few simple poses from my girlfriend. Then I picked up the book "Light on Yoga," by B.K.S. Iyengar (Amazon link: http://tinyurl.com/347qkm). And that's when my practice really began. I liked Iyengar's practical, no-nonsense approach to yoga. The book details hundreds of poses, and is very specific about how to do the poses, and for how long, and what physical benefits you can achieve by doing the pose. For example, he writes about Sarvangasana (shoulderstand), "...since the body is inverted the venous blood flows to the heart without any strain by force of gravity. Healthy blood is allowed to circulate around the back and chest. As a result, persons suffering from breathlessness, palpitation, asthma, bronchitis and throat ailments get relief ..." That's just a short excerpt, but you get the idea. Iyengar also writes about the spiritual/meditative aspects of yoga, and for me, the balance was perfect. The only problem I had was that because I was working from a book (I lived in a rural area where the yoga classes were infrequent at best), I did many of the poses incorrectly; the static images didn't do justice to the dynamic nature of even the most still asanas. Has anyone else had an inspiring book or mentor that's helped their practice and is also widely available in some form? (In other words, not a local teacher.) I heartily endorse Iyengar -- but with a teacher familiar with his teachings as a guide.
I have yet to read Light on Yoga but it is on my reading list. I do think it wouuld be difficult to learn every yoga pose from a book. There are in the least videos available where you can see the yoga poses in action. While I don't think there are commercial videos of Iyengar himself, there are plenty of videos from Iyengar teachers. A lot of the GAIAM yoga videos are taught by Iyengar teachers and use the blocks and props.
Iyengar's book "Yoga the path to holistic health" is excellent for a beginning understanding, and a bit more in depth for the basic postures than "light on life." I very much like "The woman's book of yoga & health" that shows sequences for women's health, as well as poses using chairs, and restorative yoga. "Hatha Yoga Illustrated" is good, not very in depth but has a lot of variations and pictures. Just to name a few. Erich Schiffmans book is also very good, but I don't recall the name of it at present. Geeta Iyengars book "yoga a gem for women" is very very good. But a bit difficult to read, as it lists sequences by category for such-and-such and then you have to flip to the category, and then maybe to the back of the book to look at the picture. But if you can get through all that, it's comprehensive.