Introduction*Another translation of this Chapter was published in Organization and Pathology of Thought, by David Rapaport (New York: Columbia University Press, 1951). The footnote commentary to that translation provides an introduction to Piaget’s thinking, and may serve as an introduction to the investigations and thinking contained in this volume.; Part 1 Elementary Sensorimotor Adaptations; Chapter 1 The First Stage; Chapter 2 The Second Stage; Part 2 The Intentional Sensorimotor Adaptations; Chapter 3 The Third Stage; Chapter 4 The Fourth Stage; Chapter 5 The Fifth Stage; Chapter 6 The Sixth Stage;