William Walker Atkinson (December 5, 1862 – November 22, 1932) was an attorney, merchant, publisher, and author, as well as an occultist and an American pioneer of the New Thought movement. He is also known to have been the author of the pseudonymous works attributed to Theron Q. Dumont and Yogi Ramacharaka

Atkinson was a prolific writer, and his many books achieved wide circulation among New Thought devotees and occult practitioners. He published under several pen names, including Magus Incognito, Theodore Sheldon, Theron Q. Dumont, Swami Panchadasi, Yogi Ramacharaka, Swami Bhakta Vishita, and probably other names not identified at present.

He is also popularly held to be one (if not all) of the Three Initiates who anonymously authored The Kybalion, which certainly resembles Atkinson's other writings in style and subject matter. Atkinson's two co-authors in the latter venture, if they even existed, are unknown, but speculation often includes names like Mabel Collins, Michael Whitty, Paul Foster Case, and Harriett Case.