If developmental psychologists were asked to nominate the most exciting, cutting-edge research area in the field's recent history, many would vote for the area popularly known as theory-of-mind development, the childhood acquisition of everyday, common-sense knowledge and beliefs about the mental world. This article deals with several research studies regarding what children know about mental experiences. In this article, the authors present some intuitions, together with a few illustrative studies attesting to their development. Each intuition is described by the heading of the section discussing it. Research indicates that although preschool children possess some understanding of thinking and other mental experiences, they have much more to acquire in this important area of cognitive development. This article suggests some ways that teachers and parents might occasionally and gently support these developing understandings.