The author encourages family therapists to include young children in their family therapy sessions so that they can achieve whole family understanding. For adult family therapists who want to learn how to include children, and individual child therapists who want to work with groups, the author presents a brief theory of play as well as an overview of object relations theory and its application to the family as a group. She provides many illustrations of the effective use of play as a mode of communication in family therapy with babies, latency-age children and adolescents, and concludes that play and fun support learning and growth of children and their families.