This unit of the Flexible Learning System (FLS) is concerned with the importance of play to early child development and with classroom conditions that promote productive play activity. Emphasis is put on developing skills in observing and analyzing play and understanding specific types of adult intervention in the play process. Activities and an accompanying color film, "Observing Children's Play," are designed to help adults develop specific play intervention strategies. Many activities require making observations from the film, a nonnarrated sequence of children in social play. (Observation forms are provided.) The unit is designed for use with a group of adults, to enable them to discuss why play is important for a child's growth and development; write objective descriptions of a child's play activity; determine when to provide additional resources; determine when to intervene, extend, or adapt the play situations; create a classroom environment to achieve a set of objectives; and determine when to participate as a co-player and when to redirect the play situation. Related FLS units: "Using Toys and Games with Children"; "Working with Children's Concepts"; "Managing the Preschool Classroom." (Author/SB)