Albert Ellis was an American psychologist who in 1955 developed Rational Emotive Behavior Therapy. He held M.A. and Ph.D. degrees in clinical psychology from Columbia University and founded and was the president and president emeritus of the New York City-based Albert Ellis Institute.. He is generally considered to be the grandfather of cognitive-behavioral therapies and, based on a 1982 professional survey of U.S. and Canadian psychologists, was considered as one of the most influential psychotherapists in history .