Research indicates that active adult involvement in children's play can increase the social level of play and have a beneficial impact on children's cognitive growth. To become appropriately involved in children's play, daycare providers and other adults need to understand how time, space, experiences, and materials affect children in play activities. Children require long stretches of uninterrupted time in order to sustain sociodramatic and constructive play episodes, at least 30 minutes in length. The arrangement and amount of space available for play and children's background knowledge both have a direct impact on the type of play generated. Home-living and theme-related props promote high levels of social interaction and group dramatic play. Three effective play intervention strategies are: (1) parallel play, in which an adult models appropriate play behaviors without interacting with the child; (2) co-play, in which an adult joins in a child-directed play scenario and facilitates learning and development; and (3) play training, in which an adult makes suggestions about playing or encourages children to reenact stories or fairy tales. (MDM)