Correspondence, memoranda, writings, speeches, memoirs, minutes of meetings, conference proceedings, leaflets, resolutions, bulletins, reports, clippings, newspapers, other printed matter, sound recordings, and photographs, relating to Karl Marx and the international socialist movement; the First, Second, Third and Fourth Intenationals; Russian revolutionary, anarchist and socialist movements, especially the Rossiĭskaia sotsial-demokraticheskaia rabochaia partiia (RSDRP) and its Menshevik wing; the Partiia sotsialistov-revoliutsionerov (PSR); the Russian Revolution and Civil War; Russian politics and government in the nineteenth and twentieth centuries; communism in the Soviet Union; Russian émigré politics; the Vlasov movement during World War II; and Russian displaced persons after World War II. Includes records of the RSDRP, the PSR, and other organizations; and papers of Rafail Abramovich, Pavel Aksel'rod, Viktor Chernov, Leon Trotsky, Irakliĭ TSereteli, and many others. Also includes papers of B. I. Nicolaevsky.