This history, originally published in 1962, by the then lone remaining figure in the leadership of the Russian Social Democratic Party, is an important contribution to the understanding of the Soviet October Revolution of 1917. It covers in detail the period from the February revolution of 1917 until the outbreak of the Second World War, passing through the phases of the October Revolution, the Peace of Brest-Litovsk, the Civil War, the struggle for the leadership of the party and the triumph of Stalin.