Sigmund Freud's controversial ideas have penetrated Western culture more deeply than those of any other psychologist. The 'Freudian slip', the 'Oedipus complex', 'childhood sexuality', 'libido', 'narcissism' 'penis envy', the 'castration complex', the 'id', the 'ego' and the 'superego', 'denial', 'repression', 'identification', 'projection', 'acting out', the 'pleasure principle', the 'reality principle', 'defense-mechanism' - are all taken for granted in our everyday vocabulary.