The aim of this fourth edition remains the same - to introduce students to Piaget's theory of how children construct and acquire knowledge. It has been updated and revised to incorporate the most important developments in Piagetian theory over the last several years. This fourth edition includes more information on the philosophic foundations of Piaget's thought; expanded discussion of affective development and its relatinoship to cognitive development; new material on the implications of Piaget's theory for education; and three new appendices - what Piaget's theory says about children learning to read; Piaget's constructivist theory and mathematics education; and computers, children and Piaget.