The purpose of this Spanish-language manual is to help preschool teachers better understand theoretical concepts related to children's play. Following a preface that discusses UNESCO's activities related to early childhood education, the two main sections of the manual discuss children's play between 0-2 years and 2-7 years. Each section includes information about play, suggestions for activities for teachers, and spaces for teachers to take notes. The first section discusses play from the development of reflexes up to the appearance of language, including play that involves the mouth; the senses of touch, sight, and hearing; movement; and natural objects. From 0-1 years, play uses objects to look at, touch, and hold; and objects that develop hand-eye coordination and that the baby can chew on. This play also involves the baby's dropping objects; putting objects together; recognizing color, form, and sound; and carrying objects. Between 1-2 years, children's play helps them learn to talk and to develop a sense of equilibrium. The second section discusses symbolic play, which involves the representation of reality, language, and socialization. Between 2-4 years, play can support the learning of phrases and numbers, the ability to pretend to be somebody else, drawing and coloring, and general creativity. Between 4-7 years, play can support children's abilities to organize objects and their tendency to establish friendships. The manual's final section briefly considers children's play and games after age 7 or 8, which involve more social activity and reasoning. (Contains 17 references.) (BC)