Sigmund Freud was a Jewish-Austrian neurologist and psychiatrist who co-founded the psychoanalytic school of psychology. He is best recognized for his theories of the unconscious mind, particularly concerning the method of repression; his redefinition of sexual desire as mobile and aimed at towards a broad assortment of objects; and his therapeutic methods, especially his understanding of transference in the therapeutic relationship and the supposed value of dreams as sources of insight into unconscious wishes.

Freud is frequently referred to as the father of psychoanalysis. His work has been extremely significant in the masses' imagination, popularizing such ideas as the unconscious, defense mechanisms, Freudian slips and dream symbolism, while also making a continuing impact on fields as assorted as literature, film, Marxist and feminist theories, literary criticism, philosophy, and psychology. Some of his theories, however, continue to be broadly doubted.