The original concepts of Melanie Klein and Wilfred Bion have had a profound and continuing effect on the practice of psychoanalysis. The aim of this book is to present some of their most basic ideas as simply as possible to the reader and to show, by clinical example, these ideas at work in contemporary analysis. Individual analysts contribute chapters on child analysis, the concept of unconscious phantasy, projective identification, the paranoid-schizoid and depressive positions, psychotic thinking, the relation between the container and contained, and the idea of reversible perspective in understanding `as if' personalities.