Manly Palmer Hall (1901-1990) was a Canadian-born author, lecturer, astrologer, and mystic. He is best known for his 1928 work The Secret Teachings of All Ages, an encyclopedic work on the occult and esoteric traditions. Hall was a 33rd degree Freemason, and was the founder of the Philosophical Research Society in Los Angeles, California. He wrote over 150 books and essays on topics including religion, mythology, psychology, and the occult. Hall was a proponent of the Perennial Philosophy, which holds that all religions share a common truth. He was also a proponent of the power of the human mind, and believed that the individual could use it to achieve spiritual enlightenment. Hall's legacy continues to influence the fields of philosophy, spirituality, and the occult.