Professor Piaget, who at this writing is in his eightieth year, has dedicated his life to the exploration and explanation of the genesis of knowledge. The Piagetian model rests on both a philosophical and a biological foundation, with psycholΒ ogy as the link between these two disciplines. This volume, the first in a series that will record the official Symposium Proceedings of the Jean Piaget Society, is unique in that it encompasses theoretiΒ cal, empirical, and applied aspects of Piaget's epistemology. The majority of papers in this collection represent the combined proceedings of the first and second annual symposia of the society. Professor Piaget's address, presented at the First Annual Symposium of the Jean Piaget Society in May, 1971, highlights the papers within this volume. This paper is outstanding in the clarity with which the concept of equilibration is explicated. It is the intention of the society, through this volume and subsequent ones, to extend the monumental body of knowledge provided by Piaget. The editors hope to implement transmission of the concepts within these selected papers so that they may serve as an impetus for future investigations. We are indebted to those who provided us with the invaluable editorial and secretarial assistance necessary for such an undertaking.