The subject I have been asked to talk about today is for many the most central of the psychoanalytic developments linked with the name of Melanie Klein. As with all psychoanalytic concepts it seems to me that, to understand their significance, we have to put them in the context of their history. And studying the history of Mrs Klein's ideas is different from studying that of Freud, owing to the fact that Freud is both a clinician and a theoretician, whilst Mrs Klein is almost exclusively a clinician who describes far more than she theorizes.

The evolution of Freud's thought is like a country that underwent two revolutions: the first being the fall of the theory of hysteria, and the second being the overthrow of the theory of the libido in the 1920's and its substitution by the structural theory. The work of Melanie Klein on the other hand has grown in a way more analogous to the peaceful transformation that is characteristic of English political institutions. It seems to me that Melanie Klein,