Knowledge and Development

IRVING E. SIGEL This volume of essays is a broad-gauged effort directed at reflections on the applicability of Piagetian theory to education. Identification and de­ termination of the relevance of Piagetian theory to education is of course not new. The bibliographies in this volume do attest to that assertion. Then why the persistent interest and why still another volume? Rather than deal with the relevance of each article to these issues, let us deal with the basic question of why such continue