From its very beginnings, the JIH published articles that embraced quantitative methods, but in its effort to engage as many disciplines as possible, it did much more. Over the nearly fifty years of its publishing history, it has continued to publish variegated interdisciplinary material and, in the process, to present leading-edge research. Within the last ten years, however, the journal has acquired a new role in a much more international context. The emergence of new quantitative methods has permitted the JIH to redefine interdisciplinarity. Immense data sets, with modes of interpretation drawn from the social sciences as well as from the humanities, natural sciences, and medicine, will certainly continue to revolutionize future research in history and cognate disciplines.

Understanding the complexity of the historical demographic transition—the secular change from high to low levels of mortality and fertility in Western Europe and the United States during the nineteenth and twentieth centuries—has long been a major goal of historical demography. Recent developments in individual-level life-course databases and longitudinal statistical models have allowed scholars to test ever-more complex hypotheses about the causal factors in demographic change and to develop an increasingly fine-grained image of demographic behavior before, during, and after the transition. Such studies are critical for identifying variation, both between and within societies, obscured by secular trends that appear uniform at the macro-level, and for distinguishing the contingent elements of demographic change from the universal elements. The six articles presented in this special issue bring new substantive and methodological insights to the field of historical demography—revealing the responsiveness of pre-transition fertility to changing contexts, tracking the transmission of new fertility practices, exploring the unevenness of mortality and fertility decline, and documenting the changing role of social institutions in family formation.