Psychoanalysis is a science evidently fore-ordained to growth and expansion, and among those who have extended the scope of both theory and practice Melanie Klein holds a unique place. This book is a survey of the developments in psychoanalytical knowledge resulting from her work. Her main discoveries relate to the very early phases of mental life. She recognized that the world of unconscious feeling and impulse (which we call 'phantasy') is the effective source of all human actions and reactions, modified though they are when translated into actual external behaviour or conscious thought. Although Freud first enunciated this truth, which originates in his fundamental discovery of the unconscious mind of man, he left many problems still unsolved. These have been brought nearer to a solution through Melanie Klein's consistent awareness of the significance of unconscious phantasy. Not only students of psychoanalysis and workers in related medical fields but also practising child-psychologists and the informed lay public will find this book of absorbing interest.