May, Rollo, 1909–94, American psychologist, b. Ada, Ohio. Previously a theological student and Congregational minister, May received his doctorate in clinical psychology from Columbia Univ. in 1949, and introduced to American psychology the views of the European existentialists. A pioneer of the humanistic school of psychology, his work focused on the positive aspects of human potential and on the will of individuals toward self-fulfillment. May's writings include Love and Will (1969, repr. 1981) and The Courage to Create (1975).