This book offers an overview of "constructivism", covers its historical precedents, and goes on to demonstrate that researchers have made substantial progress in understanding the mathematical experiences of children. The author argues that early numerical and other mathematical experiences are always in flux and are as much a function of the adult's as they are of the child's intentions, language and actions. For those in the mathematics education field and for cognitive and developmental psychologists, as well as educational researchers, this book aims to offer fresh concepts and analyses. This monograph on cognitive psychology, developmental psychology and mathematical education is intended for educators and researchers.