Through extensive archival research in eight different languages, Revolutionary Social Democracy introduces readers to the politics and practices of socialists in Tsarist Russia’s imperial borderlands. These parties fought for democracy and workers’ power across the entire span of the Russian Empire-from the factories of Warsaw, to the oil fields of Baku, to the autonomous parliament of Finland. Eric Blanc’s incisive study of these parties shows that the Russian Revolution was far less Russian than is commonly assumed. And the implications of this discovery challenge the long-held assumptions of historians, sociologists, and activists about the dynamics of revolutionary change under both autocratic and democratic conditions.