Leslie Hillel Farber (1912 – March 1981) was an American author, psychologist, director of therapy at Austen Riggs Center in , chairman of the faculty of the Washington School of Psychiatry, and vice president of the William Alanson White Psychiatric Foundation.
He is particularly known for his concept of "two realms of will".
Farber received his medical degree from Stanford University in 1938. He became training and supervisory analyst at the Washington Psychoanalytic Institute and director of therapy at Austen Riggs Center in .
He was chairman of the faculty of the Washington School of Psychiatry from 1955 to 1962 and member of the board of trustees of the William Alanson White Psychiatric Foundation from 1956 to 1961, of which he also served as vice president.
From 1963 to 1977, Farber was chairman of the Association of Existential Psychology and Psychiatry. He was in private practice in Manhattan after 1969.
Leslie Farber had two siblings. His brother David was a psychiatrist and his brother Manny a painter, film critic and writer.
Attention has been frequently drawn to his concept of "two realms of will" which has been cited, among others, by existential psychotherapist Irvin D. Yalom in his 1980 book Existential Psychotherapy.
According to Farber, in the first realm, will is utilitarian, moves toward an objective and is (at least potentially) conscious, whereas in the second realm, will is an unconscious phenomenon. In Farber's words:
Farber emphasized:
He indicated further examples of misdirected "willing what cannot be willed" contributing to anxiety, including for example also a "will to be creative and spontaneous" and "most urgently, will to will".
The first realm has been compared to effortless doing (wu wei) of Taoism, the second to purposive action (yu-wei according to philosophers of the time of Zhuangzi).
Edgar Z. Friedenberg has commented that Farber's conception of the will and the existential plight of man appears to have been strongly influenced by T. S. Eliot.