How children’s thinking develops and how it can be developed in education are among the most important questions in psychology. Studies of cognition in adults need to be supplemented by the developmental perspective, which often transforms them. Educational objectives will be most efficiently achieved only if we understand children’s thought. Like all important problems, the nature of developing thinking is far from simple. A wide variety of different approaches have been taken to it, and in the few years before publication had come together to produce new understanding and new ideas. Originally published in 1983, each chapter in this book addresses itself to major issues in the area and the advances that were being made at the time.