One of the most far-reaching changes brought by the First World War, at least in terms of its impact on intellectuals, was the shifting of the socialist center of gravity eastward. The unexpected success of the Bolshevik Revolution — in contrast to the dramatic failure of its Central European imitators — created a serious dilemma for those who had previously been at the center of European Marxism, the left-wing intellectuals of Germany. In rough outline, the choices left to them were as follows: first, they might support the moderate socialists and their freshly created Weimar Republic, thus eschewing revolution and scorning the Russian experiment; or second, they could accept Moscow’s leadership, join the newly formed German Communist Party, and work to undermine Weimar’s bourgeois compromise. Although rendered more immediate by the war and rise of the moderate socialists to power, these alternatives in one form or another had been at the center of socialist controversies for decades. A third course of action, however, was almost entirely a product of the radical disruption of Marxist assumptions, a disruption brought about by the war and its aftermath. This last alternative was the searching reexamination of the very foundations of Marxist theory, with the dual hope of explaining past errors and preparing for future action. This began a process that inevitably led back to the dimly lit regions of Marx’s philosophical past.