In the monograph of the candidate of historical sciences X. M. Astrakhan, a comprehensive study of the history of the main political parties of Russia between the February bourgeois-democratic and October socialist revolutions was undertaken. The book examines in detail the relationship and struggle of the Bolshevik Party with its antipode, direct and main enemy - the Cadets and with the Mensheviks and Social Revolutionaries - these "closest," in the words of V. I. Lenin, opponents of Bolshevism.