In creating psychoanalysis, Freud developed therapeutic techniques such as the use of free association and discovered transference, establishing its central role in the analytic process. Freud's redefinition of sexuality to include its infantile forms led him to formulate the Oedipus complex as the central tenet of psychoanalytical theory. His analysis of dreams as wish-fulfillments provided him with models for the clinical analysis of symptom formation and the mechanisms of repression as well as for elaboration of his theory of the unconscious. Freud postulated the existence of libido, an energy with which mental processes and structures are invested and which generates erotic attachments, and a death drive, the source of compulsive repetition, hate, aggression and neurotic guilt. In his later work Freud developed a wide-ranging interpretation and critique of religion and culture.
Freud left Austria in 1938 to escape the Nazis, and died in exile in the United Kingdom the following year. Psychoanalysis remains influential within psychology, psychiatry, and psychotherapy, and across the humanities. As such, it continues to generate extensive and highly contested debate with regard to its therapeutic efficacy, its scientific status, and whether it advances or is detrimental to the feminist cause. Nonetheless, Freud's work has suffused contemporary Western thought and popular culture. In the words of W. H. Auden's poetic tribute, by the time of Freud's death, he had become "a whole climate of opinion / under whom we conduct our different lives".