This is the first of two three-volume collections on developmental psychology which provide a comprehensive and up-to-date synthesis of the most significant publications in the field of developmental psychology over the past century. Over a total of six volumes, the editors present the benchmark readings in the discipline, including highly cited theoretical articles, empirical articles, as well as some book chapters that have had great impact in terms of presenting research findings and influencing the key debates in the field. There is a particular emphasis on recent publications to complement older, classic works, illuminating new directions in the field theoretically and methodologically, and on representing the discipline from an international perspective. In addition to the 88 key original publications included in the two collections, each of the volumes opens with an introductory editorial essay by the editors setting out the rationale behind the selection of papers in terms of their historical, theoretical and empirical importance in the development of the field. The net effect is to provide an integrated account of this very established and expansive discipline.