This paper provides an extensive discussion of children's play, including examination of theoretical, developmental, measurement, and classroom or playgroup perspectives for teachers of children between the ages of 2 and 6 years. The first section offers a brief overview of theories of play and describes several distinguishing features of play, such as intrinsic motivation and attention to means rather than ends. The development of play behavior is discussed in the second section. Specific attention is given to sensorimotor play and, more extensively, to aspects of symbolic play such as self/other relationships, object substitution, and dramatic and constructive play. The third section discusses factors contributing to individual differences in play behavior: handicaps, gender, and childrearing influences. Suggestions as to how teachers can facilitate children's play are given in the fourth section; in addition, the problem of justifying the inclusion of play in the preschool curriculum is discussed. (RH)