This monograph, illustrated with photographs and diagrams, explains how to use physical space to encourage children to involve themselves constructively in particular program activities. Program goals should be stated in specific and concrete terms to allow self-direction of young children and teacher flexibility. Analysis is made of the parts of a play space and how these parts function as a whole. Play space consists of empty space units surrounded by visible boundaries, and units containing something to play with, classified according to complexity. Play units that provide variety, complexity, and adequate amount of activity per child are considered consistent with goals for young children. Good organization of play space requires clear paths for movement and an adequate amount of empty space, as the example given demonstrates. Common problems in space development and use are discussed and solutions suggested. Examples of successful development of space, one yard and two children's centers, are fully described. Again, each spatial area discussed has been designed or altered to meet stated goals. A case study, checklists, and approaches are given to help people plan play areas. (DR)