Mme. Blavatsky defines the word Yoga in reference to rāja yoga, as follows:
(1) One of the six Darshanas or schools of India; a school of philosophy founded by Patanjali, though the real Yoga doctrine, the one that is said to have helped to prepare the world for the preaching of Buddha is attributed with good reasons to the more ancient sage Yâjnawalkya, the writer of the Shatapatha Brâhmana, of Yajur Veda,the Brihad Âranyaka,and other famous works. (2) The practice of meditations as a means of leading to spiritual liberalition. Psyscho-spiritual powers are obtained thereby, and induced escstatic states lead to the clear and correct perception of the eternal thruths, in both the visible and invisible universe.
- "A Simplified Course of Raja Yoga" by Wallace Slater. Theosophical Society in America, 2012. Available from Theosophy World.
- An Introduction To Yoga by Annie Besant
- The Yoga Aphorisms of Patanjali An Interpretation by W. Q. Judge
- The Science of Yoga by I. K. Taimni
- The Yoga of Patanjali by Ianthe Hoskins
- Yoga and the Path of Self Realization by Rohit Mehta
- The Path to Yoga by William Ross
- The Yoga Sutras of Patanjali Renee Weber
- Helena Petrovna Blavatsky, The Theosophical Glossary (Krotona, CA: Theosophical Publishing House, 1973), 380-381.