I regularly use these two books in my study of yoga. They are both well organized, well illustrated, and highly informative. Both are excellent reference tools, and explain yoga postures from an anatomical and scientific perspective.
Yoga Anatomy By Leslie Kaminoff and Amy Matthews. Published by Human Kinetics, Champain, Illinois, Second Edition, 2011. Copyright by The Breathe Trust 2007, 2012. Various indexes: by muscles, joints, position in English, position in Sanskrit, bibliography, 276 pages. ISBN: 1450400248. VSCL. An outstanding reference book on the anatomy of yoga!Hatha Yoga Illustrated: For Greater Strength, Flexibility and Focus By Martin Kirk and Brooke Boon. Photographs by Daniel DiTuro. Champaign, Illinois, Human Kinetics, 2006. Suggested readings, resources, index by Sanskrit name, index by English name, 233 pages. ISBN: 0736062033. VSCL. Practical, informative and well organized information.
My Hatha Yoga Postures List is in alphabetical order by both the English and Sanskrit names for many common Hatha Yoga postures for beginning and intermediate yoga students. The list includes coding for the kind of yoga posture, e.g., balancing, standing, supine, backbend, etc. For each posture, the list includes reference to descriptions in yoga textbooks, including the two books mentioned above. The list also includes some Chi Kung postures that I teach in many of my yoga classes. My Hatha Yoga Postures List is now 14 pages long, in a PDF format, print only, at Version 6, 10/1/2012. I also have prepared numerous one page Study Lists that might be useful to yoga students and beginning teachers.