A technique of psychoanalysis in which interpretation (2), aided by free association, is applied to the manifest content of dreams (1) in an effort to reveal their latent content which, according to psychoanalytic theory, invariably consists of unconscious wish fulfilments that are potentially disturbing to the dreamer and would interrupt sleep if they were not disguised through symbolism. Sigmund Freud (1856–1939) propounded this theory in his book The Interpretation of Dreams (1900, Standard Edition, IV-V). However, in his later book Beyond the Pleasure Principle (1920), he raised doubts about the assumption that dreams are wish fulfilments and suggested that they may serve a more primitive function (Standard Edition, XVIII, pp. 31–3). See also dreamwork, overdetermination, Wolf Man.