The period 1789-1939 was a time of dramatic, global social, political and economic transformation, with considerable ramifications for Jews and Judaism. From the dissolution of corporate status and new-found standing as individual citizens; from diverse, religious approaches to the interplay of Judaism and modernity, to competing notions of Jewish peoplehood and nationalism; from demographic growth to mass migration and relocation, this was an era of substantial change. This collection of essays explores aspects of these significant currents, with particular attention to the project of synthesizing Jewish tradition and engagement with modernity in Western Europe and the United States. An introductory essay surveys the landscape of world Jewry during the century and a half to which the volume is devoted. Trends in Sephardic and Middle Eastern Jewry as well as Eastern European Jewry are examined alongside currents in the West. The second essay explores the changing interface between Jewish law and the law of the state in the modern era. The remaining essays focus on several individuals, starting with Samson Raphael Hirsch, who encouraged, in various ways, a fusion of Jewish tradition and modernity. Particular attention is accorded the influence of the (Berlin) Hildesheimer Rabbinical Seminary on Jews in the United States engaged in this project. Though, within a decade of 1939, the world – and world Jewry – experienced seismic shifts, many of the ideas framed during the period 1789-1939 retain currency among Jews consciously rooted in the legacy of an earlier era. Reflecting the enduring impact of ideas articulated during the period explored, one essay considers how themes central to the work of an early twentieth century public intellectual, Israel Friedlaender, find expression a century later. This volume deepens understanding of the historical underpinnings of Modern (Jewish) Orthodoxy in America, a continuing manifestation of Jewish tradition in a Western key.