The year 1923 was a decisive year in the history of the international movement. It was the point at which the revolutionary movement sweeping Europe after the victory of the Bolsheviks in 1917 finally broke and began to ebb. And it was also the time at which the Soviet bureaucracy began to firmly consolidate its grip over Russian society.
The key to the situation lay in Germany where hyperinflation was driving an enormous strike movement from below and pulling millions of workers around the German Communist Party, the KPD. Toppling capitalism in Germany would have released the Soviet Union from its international isolation. The German working class was one of the largest and most powerful in the world.
Moscow was plastered with posters and slogans supporting the German uprising. Women were encouraged to pawn their wedding rings in order to send money to Germany for the revolution.
But ultimately the opportunity for a successful insurrection was missed. The KPD began its preparations for a revolution in October 1923, but it backed away from the uprising.
The Lessons of October is Trotsky's attempt to analyse why this historical opportunity was passed by - and why the Russian Revolution succeeded. For Trotsky, a successful revolution can only be made by a substantial and well-rooted party. Only with the ability of organised revolutionaries to lead an insurrection at the opportune moment can spontaneous explosions of class anger be turned into a weapon to smash the capitalist state.
But it is not enough for the party to be big and implanted enough to lead - it also has to be politically capable of leading, and able to make the leap towards challenging state power when the chance arises.
Trotsky argued that in a non-revolutionary situation a revolutionary party carries with it a degree of conservatism and inertia, which is generated by the necessary routine it needs to organise and grow in a non-revolutionary period.
But in a revolutionary period these old habits have to be overcome and the organisation has to be won to leading a struggle for state power.
Only an experienced cadre, schooled in the struggle and politically flexible, can break with the routine of propaganda and organising broad campaigns, to start preparing for the insurrection.
This ability to move from building to actively preparing to smash capitalism is what lies behind the divergent fates of the Russian and German revolutions.
It was the political leadership of Lenin who argued for the Bolsheviks to raise the slogan of "Down with the provisional government" in 1917 that prepared the party for the October Revolution. He had to do battle with those in the leadership who had failed to make the political shift and argued against the Bolsheviks seizing power in October.
In Germany the leadership of the KPD proved unable to shift towards an open challenge for state power in case their organisation was smashed in the process. As their conservatism stopped them from leading the working class to a decisive victory, the strike movement passed them by and eventually dissipated.
Trotsky's pamphlet created a fire-storm of criticism when it was published in October 1924.
Its revelations that Kamenev and Zinoviev - who together with Stalin now sat at the head of the Soviet bureaucratic machine - had opposed the October Revolution was a massive attack on their credentials.
Kamenev, Zinoviev and Stalin - the "triumvirate" - based their political legitimacy on being Old Bolsheviks who had loyally followed Lenin for years. They relied on cultivating a cult of Lenin, in which he had been an infallible leader, and had appointed them his rightful successors.
Trotsky's opponents accused him of always being closer to the Mensheviks than the Bolsheviks, and pointed to the fact that he only joined the party in 1917.
Now he had turned all that on its head, and shown how the leaders of the Soviet bureaucracy had almost allowed the Russian Revolution to pass them by.
Only 5,000 copies of The Lessons of October were produced. The rapidly degenerating leadership of the Soviet Union published an enormous tome denouncing Trotsky and accusing him of all sorts of deviations.
Trotsky's defeat opened the way for Stalin's doctrine of "socialism in one country", which renounced the international revolution in favour of competing with the Western capitalist powers for military and economic prowess.
Ultimately, the fate of his pamphlet was bound up with the very subject it covers. The failure of the German Revolution didn't just strengthen the hand of the German ruling class - the further isolation of Russia served to bolster the power of the emerging clique around Stalin. It was the failure of the KPD that meant, if indirectly, that Trotsky and his arguments could be defeated.
In this way, his book remains a vital reminder of the lessons we need to learn to ensure that we're capable of building the sort of organisation that can one day break the chains of capitalism.