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. The works published under the name of William Walker Atkinson generally treat themes related to the mental world, occultism, divination, psychic reality, and mankind's nature. They constitute a basis for what Atkinson called "New Psychology" or "New Thought".