For a half-millennium until the 1940s, the history of Poles and Jews was inextricably intertwined. In particular, from the mid-nineteenth century onwards, Poles and Jews alike were faced with sweeping economic and social changes that challenged—even threatened—livelihood, traditions, and identity. One way in which both Jews and Poles attempted to make sense of “modernity” (to use the word as shorthand for industrialization, secularization, and the communications revolution of this period) was to subscribe to one or another form of socialism. In the Polish lands, socialism and nationalism were never mutually exclusive, indeed on the whole, the two movements overlapped considerably. Again, this was just as true for Jews (Bund, Poalei Tsiyon) as for Poles (PPS). Josh Zimmerman's important book examines relations between the two most important pre-1914 Polish and Jewish socialist parties, the Bund and the PPS. Both parties aimed simultaneously to pave the way for international socialism and to develop their respective nations (Jews and Poles). Both parties rejected national chauvinism or prejudice, arguing in a Herderian vein that only when each nation developed its full potential could true internationalism reign. Despite their theoretical agreement, however, the parties frequently clashed on practical issues. Examining these practical differences, Zimmerman has much to tell us about the nature of being Jewish, Polish, and/or socialist in late imperial Russia.