There are some books which should be part of every yoga teachers’ library, some are philosophical, like Autobiography of a Yogui or the Vedas. Others are instructional like B.K.S Iyengar’s Light on Yoga or The Owner’s Manual for The Human Body by Yogui Bhajan.
Another of my personal favorites is The Key Muscles of Yoga, one of the books in The Scientific Keys Collection by author Ray Long MD. I found this book very helpful when I was doing my first Yoga Teacher Training. It is filled with colorful images of the human body and details the muscles which are active in many yoga poses. It is thorough and precise, detailing the agonist, antagonist and synergist muscles involved in a wide variety of poses, allowing anyone to truly understand what is happening on a structural and physiological level when we are performing any asana. It provides me with a secure foundation of anatomical information to be able to quickly share with my students when any doubts about a pose arise because they can visually understand the explanations through its colorful and well-rendered artistic drawings. If you are a yoga teacher, it is really worth adding to your shelf!