Originally given as a series of lectures intended to acquaint the general public with recent developments in psychoanalytic thinking and practice, the papers in this book cover the most fundamental ideas put forward by Klein and Bion; child analysis, Klein's use of the concepts of unconscious phantasy, projective identification, the paranoid-schizoid and depressive positions, Bion's study of psychotic thinking, his ideas of the relation between container and contained, and the usefulness of the ideas of reversible perspective in understanding 'as if' personalities. In particular, this book provides an eminently readable and authoritative introduction to some of the most original and controversial concepts ever put forward in psychoanalysis.