Klein's theoretical work gradually centered on a highly speculative hypothesis propounded by Freud, which stated that life may be an anomaly, that it is drawn toward an inorganic state, and therefore, in an unspecified sense, contains an instinct to die. In psychological terms Eros, the sustaining and uniting principle of life, is thereby postulated to have a companion force, Thanatos, which seeks to terminate and disintegrate life.
Examining ultra-aggressive fantasies of hate, envy, and greed in very young, very ill children, Melanie Klein put forth the interpretation that the human psyche is in a constant oscillation depending on whether Eros or Thanatos is in the fore. She calls the state of the psyche, when the sustaining principle of life is in domination, the depressive position. The psychological state corresponding to the disintegrating tendency of life she gives the name the paranoid-schizoid position.
Melanie Klein's insistence on regarding aggression as an important force in its own right when analyzing children brought her into conflict with Anna Freud, the other major child psychotherapist working in England at the time. Many controversies arose from this conflict.
Melanie Klein's collected works are encapsulated in two volumes:
- Love, Guilt and Reparation: And Other Works 1921-1945, Paperback, Free Press 2002
- Envy and Gratitude
- The Psycho-Analysis of Children (1932)
Other books on Melanie Klein:
- C. Fred Alford, Melanie Klein and Critical Social Theory: An Account of Politics, Art, and Reason Based on Her Psychoanalytic Theory, Yale UP 1990
- P. Grosskurth, Melanie Klein: Her World and Her Work, Karnac Books 1987 - A thorough biography
- Robert Hinshelwood, Susan Robinson, Oscar Zarate, Introducing Melanie Klein, Icon Books UK 2003
- Meira Likierman, "Melanie Klein, Her Work in Context" Continuum International, Paperback, 2002
- Jacqueline Rose, Why War?-- Psychoanalysis, Politics, and the Return to Melanie Klein, Blackwell Publishers 1993