Much water passes under the bridge between Lenin's death in 1924 and Althusser's rise to theoretical prominence in the late 1950s. The Soviet Union is passed to Stalin's control; Gramsci is imprisoned in Regina Coeli in 1926; Trotsky is assassinated in Mexico in 1940; Heidegger is recuperated by Sartre's Being and Nothingness in 1943; Mao defeats Chiang Kai-Shek in China's communist revolution of 1949; Stalin dies in 1953; and in 1956, on one side of the world, the Algerian War of Independence begins, while on the other Nikita Khrushchev announces a programme of de-Stalinisation. Given the tumultuous decades separating Lenin's death from Althusser's rising star, what can possibly justify leaping over these events? A clue lies in Althusser's persistently liminal status in the history of twentieth-century philosophy – too Marxist for the new poststructuralist generation, too close to poststructuralism for orthodox Marxists to accept. Althusser remains an oddity in mediating these two visions of historical change: on the one side, classical Marxism, which subsumes events into a succession of necessary historical stages; and on the other, the postmodern emphasis on contingent and singular events, disarticulated from historical processes. The reason for carving this book around Althusser's theoretical persona is to make a case, for better and for worse, about the importance of his mediating role.

The chapters on Hegel, Marx and Lenin in Part I of this book concluded that classical Marxism's teleological notion of quantity-quality leaps cannot think discontinuous events. The chapters on Althusser, Badiou and Meillassoux grapple with a different problem. Although sharing a rejection of the Hegelian dialectic and grasping the discontinuous nature of events, we see that these thinkers are led (sometimes consciously, sometimes unconsciously) towards shoring up the authority of theory. The speculative-rationalist excesses of this genealogy, present in classical dialectical materialism though tempered by the conviction that its historical schemas should stand up to empirical verification, are thereby shown to point in a troublingly Platonic direction.