Edgar Cayce (March 18, 1877 – January 3, 1945) was an American clairvoyant who answered questions on subjects as varied as healing, reincarnation, wars, Atlantis, and future events while allegedly asleep. A biographer gave him the nickname, The Sleeping Prophet. A nonprofit organization, the Association for Research and Enlightenment, was founded to facilitate the study of Cayce's work.

Some consider him the true founder and a principal source of the most characteristic beliefs of the New Age movement.

Cayce is also notable for his contributions to the notions of diet and health, particularly the issues of food combining, acid/alkaline diet, and the therapeutic use of food.