This book is something new in psychoanalytical exposition both in its subject matter and its form of presentation. It attempts to convey, in everyday language understandable to the layman, some of the unconscious mental processes which underlie the feelings and action of normal, adult men and women. The characteristic feature of human psychology is the intense and continual interplay of the impulses of love on the one hand and hatred and agression on the other. Joan Riviere opens this joint study with an analysis of hate, greed, and aggression, and in the second section Melanie Klein talks about the forces of love, guilt, and reparation. Tracing the impulses in question back to their origins in infancy, the authors point out many features of adult mental life which evidence the persistence of earlier modes of thinking. Then they discuss some of the "infinitely various, subtle and complicated adaptations" by means of which each individual tries, all his life, to keep a balance between the life-brining and the destructive elements of his nature in order to achieve the maximum of security and gratification.