"Three Initiates" is the pseudonym for the author(s) of a book entitled "The Kybalion," which was first published in 1908. The true identity of the Three Initiates has never been conclusively revealed, though various speculations have suggested that it could be a single person or a group of individuals. The book is devoted to the study of Hermetic philosophy and is known for encapsulating the principles of Hermeticism, attributed to the legendary sage Hermes Trismegistus. It has been influential in the New Thought Movement and in the Western esoteric tradition, but because of the anonymous nature of the "Three Initiates," little concrete biographical information is available about the author(s). Some have speculated that the principal author could have been William Walker Atkinson, a prolific writer and pioneer in the New Thought Movement, but this hasn't been definitively established.