Play therapy is based on developmental principles and, thus, provides, through play, developmentally appropriate means of expression and communication for children. Therefore, skill in using play therapy is an essential tool for mental health professionals who work with children. Therapeutic play allows children the opportunity to express themselves fully and at their own pace with the assurance that they will be understood and accepted. This document is divided into the following parts: rationale for play therapy; the process of play therapy; toys and materials; setting limits in play therapy; play therapy research and results, professional training; and future trends in play therapy. (Contains 3 references.) (MKA)