This book explores and underlines the thesis that developmental psychology cannot function fruitfully without systematic historical scholarship. Scientific thinking not only depends on empirical-analytical research, but also requires self-reflection and critical thinking about the discipline’s foundations and history. The relevance of history was made especially clear in the writings of William Kessen, who analyzed how both children and child development are shaped "by the larger cultural forces of political maneuverings, practical economics, and implicit ideological commitments." As a corollary, he emphasized that the science of developmental psychology itself is culturally and historically shaped in significant ways. Discussing the implications of these insights in the book’s introduction, Koops and Kessel stress that we need a Historical Developmental Psychology. In the book’s following chapters, historians of childhood – Mintz, Stearns, Lassonde, Sandin, and Vicedo – demonstrate how conceptions of childhood vary across historical time and sociocultural space. These foundational variations are specified by these historians and by developmental psychologists – Harris and Keller – in the research domains of emotions, attachment, and parenting. This collection demonstrates the importance of bridging, both intellectually and institutionally, the gap between the research of historians, and both current and future research of developmental psychologists. This book was originally published as a special issue of the European Journal of Developmental Psychology.