This discussion seeks to answer some perennial questions on the left: what kind of organisation/party is needed to win socialism? What is the relationship between a revolutionary party and the working class, whose interests it seeks to advance? Vladimir Lenin, in the heat of decades of struggle and repression, attempted to answer these questions when he and other activists built the Russian Bolshevik party. They demonstrated that a democratic and thoroughly revolutionary party, based in the most radical parts of the working class, had to be built in order for a workers’ revolution to succeed. Since then, Lenin’s theory of the revolutionary party has been much maligned. This talk will revive it for a modern context, where rebuilding the forces of the left is an urgent task.