This issue is the second in a two-part series that commemorates the 50th anniversary of Merrill-Palmer Quarterly: A Journal of Developmental Psychology. Like its July 2004 predecessor, this issue contains invited commentaries written by senior investigators whose research programs and accomplishments span many years within this epoch. Collectively, the content of these commentaries presents historical analyses of pivotal accomplishments within various subdisciplines of the human developmental sciences, and appraisals of the contemporary status and future directions of specific areas of investigation
