Sigmund Freud, the father of psychoanalysis, published The Interpretation of Dreams in 1899. In this book, he explains his theory of the unconscious with regard to dream interpretation and explores what would later become the notion of the Oedipus complex.
According to Freud, there are two mental processes that lead to the formation of dreams. In the first process, unconscious forces create a wish that is expressed in the dream, and in the second, censorship distorts the wish’s expression forcibly. All dreams, in Freud’s opinion, are manifestations of “wish fulfilment”. According to him, dreams are like picture puzzles that, although they may initially seem absurd and pointless, can be decoded to reveal a “poetical sentence of the greatest beauty and meaning.”