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.
https://en.wikipedia.org/wiki/Aaron_Beck