The book explores the complex process of acute class struggle in all Cossack regions of Russia during the October Revolution and Civil War. An extensive archival material, data from the periodical press of that time, scientific, historical and memoir literature shows the complex and contradictory transition of the labor Cossacks to the side of Soviet power, reveals the leading role of the Central Committee of the RCP (B.), SNK, V.I. Lenin and local Bolshevik organizations in the defeat of the Cossack counter-revolution in 1917-1920.