The Berlin council movement of 1919–20 proves that there was a left alternative beyond Social Democracy and Stalinism in the German Revolution. The movement combined an impressive mass mobilisation with extensive socialist and democratic aspirations that pointed far beyond the Weimar order. Berlin was not just the centre of the November Revolution of 1918, but also the most important arena of the Second Revolution that followed. For the first time, the movement is analysed here in all its diversity and on the basis of a broad range of sources. Beside the workers' and factory councils, it also includes councils of students, women, the unemployed and intellectuals. Central events such as the 1919 general strike and the struggle against the Kapp Putsch of 1920 are also examined.