Abraham Maslow (1908 - 1970)
Abraham Harold Maslow was born April 1, 1908 in Brooklyn, New York.
He was a child of Jewish Russian immigrants to the United States. He studied at the University of Wisconsin, where he received his B.A. (1930), his M.A. (1931), and his Ph.D. (1934) in psychology.
Theory
Hierarchy of Needs and Self-Actualization
Maslow's hierarchy of needs is often depicted as a pyramid consisting of five levels: the four lower levels are grouped together as deficit needs, the top level is referred to as being needs. While deficit needs can be met, being needs are a continuing driving force. The basic idea of this hierarchy is, that higher needs come into focus only after all needs lower in the pyramid are met. Growth forces result in upward movement on the hierarchy, whereas regressive forces push prepotent needs down in the hierarchy.
The deficit needs (also termed D-needs by Maslow) are Physiological, Safety, Love, Esteem, Being, and Self-actualization.
Self-actualization (a term originated by Kurt Goldstein) is the instinctoid need of a human to make the most of their unique abilities. Maslow described it as:
A musician must make music, the artist must paint, a poet must write, if he is to be ultimately at peace with himself. What a man can be, he must be. This need we may call self-actualisation. (Motivation and Personality, 1954)
While other needs can be met fully, self-actualization is seen as "growing", i.e. as a continuing driving force. This is related to tikkun olam in the Jewish tradition — using one's skills to fix what is broken in the world.