Sigmund Freud (6 May 1856 – 23 September 1939), born Sigismund Schlomo Freud, is an Austrian neurologist who became known as the founding father of psychoanalysis.

Freud's parents were poor, but they ensured his education.

Interested in law as a student, he moves instead into medicine, undertaking research into cerebral palsy, aphasia and microscopic neuroanatomy.

He goes on to develop theories about the unconscious mind and the mechanism of repression, and establishes the field of verbal psychotherapy by creating psychoanalysis, a clinical method for treating psychopathology through dialogue between a patient (or "analysand") and a psychoanalyst.

Though psychoanalysis has declined as a therapeutic practice, it has helped inspire the development of many other forms of psychotherapy, some diverging from Freud's original ideas and approach.

Freud postulates the existence of libido (an energy with which mental process and structures are invested), develops therapeutic techniques such as the use of free association (in which patients report their thoughts without reservation and make no attempt to concentrate while doing so), discovers transference (the process by which patients displace on to their analysts feelings based on their experience of earlier figures in their lives) and establishes its central role in the analytic process, and proposes that dreams help to preserve sleep by representing as fulfilled wishes that would otherwise awake the dreamer.

He is also a prolific essayist, drawing on psychoanalysis to contribute to the interpretation and critique of culture.

Psychoanalysis remains influential within psychiatry and across the humanities, though some critics see it as pseudoscientific and sexist, and a study in 2008 suggested it had been marginalized within university psychology departments.