A successful workers' revolution in Germany in 1923 would have changed the entire course of the last century's history. A second workers' state - in one of the most advanced industrial countries - would have made nonsense of Stalin's slogan of 'socialism in one country' and enormously enhanced the chances of spreading the revolution to France, Britain and Italy. The two great tyrannies of the century, Stalin's Russia and Hitler's Germany - with their host of imitators and would-be imitators - would have been aborted. Of course there would have been other dangers, other possibilities of defeat still to face. But the scales would have been shifted significantly in favour of socialism.
One person who had the opportunity to observe and analyse the events in Germany 1923 at first hand was Victor Serge.
In some ways the world of the Weimar republic may seem very remote to modern readers. Yet there are many features of Serge's account that remind us that we are still confronting the same bankrupt social system.
History does not repeat itself, but a knowledge of the past arms us for the future. Serge himself summed it up beautifully in his novel Birth of our Power, when he reflected that defeated revolutionaries could look forward to the success in the future of others, 'infinitely different from us, infinitely like us'.