Karl Abraham was an early German psychoanalyst, and a correspondent of Sigmund Freud, who called him his 'best pupil' . He founded the Berlin Psychoanalytic Institute, and was the president of the International Psychoanalytical Association from 1914 to 1918 and again in 1925.

Karl Abraham collaborated with Freud on the understanding of manic-depressive illness, leading to Freud's paper on 'Mourning and Melancholia' in 1917. He was the analyst of Melanie Klein during 1924-1925, and of a number of other British psychoanalysts, including Edward Glover, James Glover, and Alix Strachey. He was a mentor for an influential group of German analysts, including Karen Horney, Helene Deutsch, and Franz Alexander.