The collection opens a series of publications of documents on the activities of the Petrograd Soviet of Workers' and Soldiers' Deputies from February 27 to October 25, 1917. The materials placed in this volume contain practically unknown today, in most cases, unique documents on the most important political events of the end of February-March 1917 - on the formation and beginning of the activities of the Council, relations between the Soviet and the Provisional Government, the position of the Bolshevik Party, Socialist Revolutionaries, Mensheviks.