The Shambhala Guide to Yoga by Georg Feuerstein (Shambhala, 1996).
Ka: Stories of the Mind and Gods of India by Roberto Calasso (Knopf, 1998).
Hatha Yoga: The Hidden Language by Swami Sivananda Radha (Timeless, 1987).
Yoga-Sutras of Patanjali with the Exposition of Vyasa: Volume 1, Samadhi-pada by Pandit Usharbudh Arya (Himalayan International Institute, 1986).
The Synthesis of Yoga by Sri Aurobindo (Sri Aurobindo Ashram, 1988).
Yoga: Immortality and Freedom by Mircea Eliade (Princeton University Press, 1958).
The Serpent Power: The Secrets of Tantric and Shaktic Yoga by Sir John Woodroffe (Arthur Avalon) (Dover, 1974).
Philosophies of India by Heinrich Zimmer (Princeton University Press, 1951).