Now more than ever, understanding the nature of aggression is crucial to our understanding of individual and social ills produced by the accumulation in humans of hostile destructiveness. The Development of Aggression in Early Childhood, first published in 1979, is here reissued in a revised edition because the author's multi-trends theory of aggression and its clinical and social applications have held up cogently and productively for nearly thirty years. Dr. Parens' observation-based explication of highly different forms or trends of aggression is experience-near and is, he argues, of greater heuristic merit than the assumption that humans are inherently 'seething cauldrons of destructive excitations.' The responsibility for the hostility and hate we experience in our world today, according to Dr. Parens, lies with the way we are reared, educated, and treated individually and socially-and not with the assumption that we are ab ovo driven to destroy. In this revised edition, Parens' theory is offset by a two-part Preface that provides a historical overview of the multitudinous theories of aggression in psychoanalytic thought and discusses the clinical applications of the multi-trends theory of aggression with case studies and further clinical theorizing about hostile destructiveness and clinical technique. This book is intended not only for mental health professionals of all degrees and orientations, but also for all those who tend children, be they caregivers, pediatricians, educators, or pastoral counselors.