The book, based on materials from German archives and published sources, highlights the economic and domestic political situation of Germany and the mass anti-war movement in the summer and autumn of 1917. Much attention is paid to the October political crisis in Germany and the exposure of the aggressive program of German imperialism in 1917, especially in relation to Russia. The author shows what influence the February bourgeois-democratic revolution in Russia had on Germany and the German labor movement. The book traces the ideological development of the German left, shows the connections of V.I. Lenin with the left, the ways of penetration of Leninist ideas into Germany and their influence on the German left.