Melanie Klein extended and developed Sigmund Freud’s understanding of the unconscious mind. By analysing children’s play, much as Freud had analysed dreams, she explored the uncharted territory of the mind of the infant, finding an early Oedipus complex and the earliest roots of the superego.
Klein's understanding of the child’s deepest fears, and its defences against them, enabled her to make original theoretical contributions to psychoanalysis, most notably the ‘paranoid-schizoid position’ and the ‘depressive position', and she showed how these primitive mental states impact on the adult. Her groundbreaking theories have been taken up and developed by later generations of psychoanalysts. Below is a selection of concepts developed by Klein and her followers.
The definitions are reproduced from the The New Dictionary of Kleinian Thought by Elizabeth Bott Spillius, Jane Milton, Penelope Garvey, Cyril Couve and Deborah Steiner (Routledge, 2011).