Jean Piaget (1896-1980) was listed among the 100 most important persons in the twentieth century by Time magazine, and his work - with its distinctive account of human development - has had a tremendous influence on a range of disciplines from philosophy to education, and notably in developmental psychology. The Cambridge Companion to Piaget provides a comprehensive introduction to different aspects of Piaget's work in a manner that does not eschew engagement with the complexities of subjects or debates yet is accessible to upper-level undergraduate students. Each chapter is a specially commissioned essay written by an expert on the subject matter. Thus, the book will also be of interest to academic psychologists, educational psychologists, and philosophers.