When the German-Jewish philosopher Franz Rosenzweig entitled his 1926 collection of essays on Jewish and universal cultural topics Zweistromland -- a land of two rivers -- he meant to underscore, indeed celebrate, the fact that German-Jewish culture is nurtured by both German culture and the Jewish religious and cultural heritage. In this thought-provoking book, Paul Mendes-Flohr explores through the prism of Rosenzweig's image how German Jews have understood and contended with their twofold spiritual patrimony. He deepens the discussion to consider also how the German-Jewish experience bears upon the general modern experience of living with multiple cultural identities. German Jews assimilated the cultural values of Germany but were not themselves assimilated into German society, Mendes-Flohr contends. Yet, by virtue of their adoption of values sponsored by enlightened German discourse, they were no longer unambiguously Jewish. The author discusses how their identity and cultural loyalty became fractured and how German Jews -- dike other Jews and indeed like all denizens of the modern world -- were obliged to confront the challenges of living with plural identities and cultural affiliations.