The period 1923-27 witnessed a great battle between Trotsky and Stalin over the fate of the Russian revolution and the Communist International. It ended with the banishment of Trotsky and the entrenchment of the bureaucracy. Now Trotsky recognised his adversary as the "gravedigger of the revolution".
How could Stalin, a man scarcely noticed in the great events of 1917, triumph over Trotsky, the leader of the revolution and the Red Army, the great orator and theoretician?
The answer lies not in personal ability but in the class struggle. The tide of history was ebbing away from the revolutionary tradition, weakening the working class both in Russia and internationally. Just as great leaders were forged in the high points of struggle, so defeat and degeneration lent weight to the mediocrities who represented all the deference and prejudice of the old regime.
But Trotsky's defeat was by no means inevitable. Three great convulsions - in Germany in 1923, in Britain in 1926 and in China in 1927 - all provided opportunities for the flow of history to be reversed by working class victory.
Tony Cliff charts each of these struggles - and the battles within Russia itself - to show how Trotsky's position was vindicated, but tragically never implemented.