The first yoga book I bought was How to Use Yoga, by Mira Mehta. It’s very clear, with lots of pictures. It covers many basic poses, and in the back it gives the sequences for a couple of years worth of home practice. The sequences show thumbnail photos of the asanas, so once you know how to do the poses you don’t have to do a lot of flipping back and forth in the book.
I think it was out of print for a while, because I kept seeing it in discount places like TJ Maxx and Tuesday Morning, but I haven’t seen it there lately. I hope I come across it again, because I gave away my last copy. It’s a perfect beginner’s book, especially for someone who has already attended some Iyengar classes.
Practice Notes 
Hi:
I would like to recommend another book on how to do yoga that is suitable for beginners. It is Yoga the Path to Holistic Health by BKS Iyengar. This book includes very thorough instructions and multiple photographs showing how to do many of the basic yoga poses.
Best wishes,
Deborah Rummelhart, author of Where Are My Ankles? How Iyengar Yoga Rescued Me From Stress, Fear and a Very Bad Back. Read sample chapters and get a coupon for a free yoga class honored at 45 yoga studios nationwide at http://www.funnypath.com .
Oh yes, Deborah, I completely agree. The Mira Mehta book is an easier entry – cheaper and less overwhelming, but the big Iyengar book is really much more comprehensive.