The activities of the Bolshevik Party during the First World War were studied on an extensive and diverse historical material. The first part of the monograph examines the activities of the foreign Russian bureau of the Central Committee of the RSDLP, the capital and local party organizations of the Bolsheviks during the war. The second part is devoted to the study of memoirs about the labor movement in Russia during the First World War, including propaganda work, the organization of strike struggle, and the boycott of military-industrial committees. Designed for scientists, teachers, graduate students, students and everyone interested in Russian history.