Few fields are as riddled with terminological indecision as “German Jewish thought.” One cannot invoke this sphere without immediately bumping up against essential questions of definition. Should membership within its bounds be reserved for those who wrote, primarily, as Jews for Jews, even if in a non-Jewish language? Or should its borders be expanded substantially to include Jewish contributions to secular German thought—or, perhaps more aptly put, secular thought in German, in order not to exclude the vast number of Central European Jewish innovators who wrote in the language? If one takes the latter route, the problems only proliferate, for the question then ensues, what makes any of these supposed Jewish contributions Jewish? How is the Jewishness of a particular work, school of thought, or sensibility to be gauged and assessed? How does one avoid the risk of reading too much in—or too little? How does one steer clear of reducing Jewishness to some stable core or essence, without relying on a notion so broad and diffuse as to be effectively meaningless? And always lurking is the question whether, in imputing Jewishness to a cultural product or outlook, one has betrayed its creator, who would have recoiled at being labeled a “Jewish” author or artist. These problems are not peculiar to German Jewish intellectual history. They arise wherever and whenever Jews have been disproportionately prominent in the shaping of secular culture—for instance, in the writing of the “New York intellectuals” in the postwar United States. But the role of authors and artists of German Jewish background proved especially pronounced even after many, like Hannah Arendt or Leo Strauss, emigrated to escape the Nazis. In their new environments, they remained active participants in intellectual life, and the question remains whether they were carrying on the tradition of German Jewish thought.