Historians have largely tended to regard Polish Jewish history and German Jewish history, from the Middle Ages to the present, as playing out solely within national boundaries, thereby ignoring the interactions that have in practice shaped Jewish cultural life. Geographical proximity has meant that Jews from both countries have been linked through kinship ties as well as shared economic, cultural, and linguistic realities. The complexity of this relationship and its consequences have been only partially reflected in scholarship. This volume takes a different approach, shifting the focus away from the nationally distinct to investigate instead mutual influences and interactions. Moving beyond the traditional paradigms that characterize Polish Jewry as 'authentic' and German Jewry as 'modernizing', it challenges the sharp historiographic division between these two communities and opens up a nuanced understanding of modern European Jewish history.