A critical analysis is made of the content and assumptions of the many theories or explanations for play behavior. The seven chapters of the book are as follows. Chapter One, A Purview of the Problems, is a brief overview of the problems inherent in attempting to manage play, and the arguments for and against. The second chapter, Definitions of Play, defines play. Chapter Three, Classical Theories of Play, analyzes these theories that have in common their age and a concern with the inherent nature of play that was common across a species. The fourth chapter, Recent Theories of Play, deals with more recent explanations that have in common a recognition of the importance of preceding experiences of the individual player. Chapter Five, Modern Theories of Play, reviews in detail contemporary thinking on play and its motivation. The sixth chapter, An Integration, integrates three theories that seem to hold most promise of explaining play. Chapter Seven, Implications for Practice, takes the problems from the viewpoint of the practitioner, sketching in principles of operation derived from Chapter Six. Many references are provided. (Author/DB)