The claim of Israel and its apologists to represent Jews everywhere, the growth of the antisemitic far right, and the approach of the left to the Jewish question, are central issues today. A knowledge of the role of Jews in the past aids understanding of these debates. This book recovers some of that long-neglected history. Before the Second World War the majority of Jews were working class and part of a wider struggle alongside their non-Jewish comrades on the left. The book celebrates Jewish radicalism from the Tsarist Empire to Poland and Germany, from London to New York. To illuminate this background the issue of Jewish identity is analysed along political, cultural, and sociological lines. Fighting oppression and exploitation took numerous political forms, including left Zionism, Bundism and revolutionary Marxism. Far from the Zionist stereotype of the ultimate victims, Jews were revolutionaries, resistance fighters and firebrands. This inspiring radical tradition was ultimately checked by the callous indifference of capitalist governments to refugees and the horror of Auschwitz. However, its lessons must be passed on to inform working class and anti-imperialist struggles in a world in crisis.