Aaron T. Beck, American psychiatrist and academic
Aaron Temkin Beck (July 18, 1921 – November 1, 2021) was an American psychiatrist who was a professor in the department of psychiatry at the University of Pennsylvania. He is regarded as the father of cognitive therapy and cognitive behavioral therapy (CBT). His pioneering methods are widely used in the treatment of clinical depression and various anxiety disorders. Beck also developed self-report measures for depression and anxiety, notably the Beck Depression Inventory (BDI), which became one of the most widely used instruments for measuring the severity of depression. In 1994 he and his daughter, psychologist Judith S. Beck, founded the nonprofit Beck Institute for Cognitive Behavior Therapy, which provides CBT treatment and training, as well as research. Beck served as President Emeritus of the organization up until his death.

Beck was noted for his writings on psychotherapy, psychopathology, suicide, and psychometrics. He published more than 600 professional journal articles, and authored or co-authored 25 books. He was named one of the "Americans in history who shaped the face of American psychiatry", and one of the "five most influential psychotherapists of all time" by The American Psychologist in July 1989. His work at the University of Pennsylvania inspired Martin Seligman to refine his own cognitive techniques and later work on learned helplessness.