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...