Summarized in this volume are concepts, presented and developed at a roundtable discussion by scientists and child health professionals, focusing on aspects of children's play behavior. Participants sought to answer three questions: (1) What is play behavior and what is known about it? (2) How does play contribute to infant and child development? and (3) How can the quality of children's play experiences be improved? In answering these questions, participants discussed types and characteristics of play and reported contributions of play to children's physical, cognitive, emotional, and social development. Ways society benefits from play were noted. Also discussed were criteria for evaluating play and ways of improving play situations through the provision of appropriate playthings and sensitive adult intervention. The importance of taking into account individual developmental differences when evaluating children's play behavior was pointed out. The concluding section of the summary mentions additional related resources. (RH)