There are numerous resources for learning about hatha yoga. A list of books is provided below. Websites change continually, so they are not listed, but they are easy to find. There is no lack of yoga information on the Internet. There is also no lack of misinformation and incomplete information. Don’t believe all you read or see.
“Back to basics” is a valuable approach. Go back to what the masters actually said, not what somebody else says they said. The pure source is the most honest: re-interpretations and commentary can be useful, but they can also be erroneous or misguided by motivations of the writers.
A cautionary note: as you would expect, the details of the older texts don’t match Western knowledge of health, medicine, and physiology. Some of this is due to cultural and environmental variations, some to different views of the world. Other information is simply factually incorrect in light of modern knowledge. Bear this in mind, but don’t throw out all of a master’s knowledge because he cautions against eating vegetables (this is a true example).
Many contemporary teachers and schools identify with a label (e.g. Iyengar yoga), but many do not. Learn about the masters, then you can pursue an open-minded informed investigation and evaluation of resources beyond the limits of labels. There are thousands of books, web pages, and videos on yoga.
Ancient yoga texts:
Yoga Sutras by Patanjali
Yoga Yajnavalkya
Hatha Yoga Pradipika by Svatmarama (4 and 10 chapter versions)
Gheranda Samhita
Shiva Samhita
These texts are available in several translations from the original Sanskrit. Reading them in different translations is valuable, as meanings of verses can vary subtly with different words.
20th Century Hatha Yoga Texts
T. Krishnamacharya: Yoga Makaranda, Parts I and II
A.G. Mohan: Yoga for Body, Breath, and Mind; Yoga Therapy
T.K.V. Desikachar: The Heart of Yoga; Health, Healing, and Beyond
B.K.S. Iyengar: Light on Yoga; Yoga: the Path to Holistic Health
Swami Sivananda: Hatha Yoga
K. Pattabhi Jois: Yoga Mala
Indra Devi: Forever Young, Forever Healthy; Yoga for Americans/Yoga for You
Many of the masters were prolific in their written output; others were stingy. It is always interesting to read their thoughts on yoga and other topics. Try to ensure that the material is genuine, i.e. prepared by the master and issued by the master during his lifetime.
Which does not mean that only the masters have something useful to say. There are wonderful books by yoga teachers and practitioners who may or may not be claiming to follow a particular master’s direction. My library contains dozens of such books that I refer to when I am evaluating and improving my yoga practice. However, I still rely on basic principles, using the additional books as supplementary information.
Speaking of which, sometimes modern hatha yoga anatomy books can be educational. The old texts purport to be interested in anatomy and physiology, but the authors really didn’t have the necessary scientific tools. Today some authors are able to blend current Western knowledge of biomechanics, biochemistry, etc. with Eastern knowledge, for example regarding the yogic approach to breath (prana). For people interested in physiological details of hatha yoga, some good books are available.
Finally, let me mention the existence of books about the history of yoga and its evolution -- specifically books written from a point of view outside the inner circle of the Indian yoga community. The Yoga Tradition by Georg Feuerstein is excellent. Other books can provide intriguing speculation about yoga in addition to a different perspective. If you are interested in broadening your perspective of yoga, check out writings by Mark Singleton (e.g. Yoga Body: The Origins of Modern Posture Practice) and Elizabeth De Michelis (e.g. A History of Modern Yoga). Singleton's book is particularly educational regarding hatha yoga, in that it demonstrates potential communication among various physical fitness communities worldwide in the early 1900s that likely influenced all parties, including Indian asana practitioners.
Most of the texts mentioned above provide lists of additional reading material, in the form of footnotes, references, and bibliographies. These lists in turn provide further lists; the well never runs dry. Alas, the well's output is not always pure. Cumulative evidence demonstrates that there is no Ultimate Yoga Truth or Ultimate Factually Verified Yoga History. All that exists is the research & writings of well-meaning people who are only human and frequently arrive at different interpretations & conclusions from the same available data. As a society we have grown accustomed to science that can calculate pi accurately to an infinite number of decimal places, and engineering that can build a spacecraft to orbit Pluto and send video back to Earth. The history of yoga, or any other human endeavor, doesn't work that way. History is incomplete, inaccurate, and driven by the extremes of noble integrity, pure self-interest, and everything in between. You take what you can get, are grateful for it, and move forward on your own path.
Finally, the ultimate disclaimer: hatha yoga documents of which nobody in the Western world is aware may exist. As the Dead Sea Scrolls rocked Christianity, yoga documents in ancient Sanskrit may lie undiscovered or languishing in a minor library in the hinterlands of India. This possibility excites and humbles everyone interested in any form of yoga.
A reminder: this website concerns itself with Hatha Yoga as defined on the Hatha Yoga Pradipika page. This definition leads to inclusion of certain yoga masters and exclusion of other master yogis whose practices involve physical actions, but not of a kind to justify mention on this website. One excellent example is Paramahansa Yogananda, founder of a Christ-centered style of yoga termed Kriya Yoga that uses ”energization exercises.” Followers of this yoga style may well believe that they are performing hatha yoga. I humbly acknowledge their viewpoint, and similar views of followers of other physical yoga sects, and I ask simply for their understanding that I couldn’t include everybody on the site, so I made my selection in what I considered a rational way.
