Boris Ivanovich Nicolaevsky (Russian: Бори́с Ива́нович Никола́евский) (1887–1966) was a revolutionary Russian Marxist activist, archivist, and historian. Nicolaevsky is best remembered as one of the leading Menshevik public intellectuals of the 20th Century.
Nicolaevsky became a member of the Menshevik wing of the Russian Social Democratic Labor Party when he was still a youth. He was subsequently arrested eight times and sent into Siberian exile three times by the Tsarist government.
As an active Menshevik, Nicolaevsky was arrested by the Soviet secret police in 1921 and deported from Soviet Russia in 1922. He subsequently moved to Berlin, where he was associated with the Marx-Engels Institute there, before becoming the director of the International Institute of Social History in Amsterdam, repository of the archives of the Socialist International.
Many individuals of all political complexions confided their archival treasures to him. The failed negotiations over the Soviet offer to purchase the Marx-Engels Archive and the politically motivated theft from Nicolaevsky's office of Leon Trotsky's archives affected him greatly in 1936. His extensive collection of revolutionary documents is now held by the Hoover Institution Archives in Palo Alto, California.
Nicolaevsky is the author of the book Karl Marx: Man and Fighter, first published in German in 1933. It was translated into English by Otto Mänchen-Helfen and published in 1936. Some subsequent English editions restore the notes, appendices, and bibliography omitted from the first English edition.
Nicolaevsky emigrated to the United States in 1942, where he remained until his death, lecturing at various American universities and serving as the curator of the Hoover Institution Archives.
Nicolaevsky also wrote "Forced Labor in Soviet Russia", with David Dallin, published in 1948, which was one of the first books to give a truthful and documented account of the scale of the USSR's labour camp system.
His other works included Power and the Soviet Elite and Aseff the Spy. He also wrote an essay "On the History of the Bolshevik Centre" and an unfinished biography of Georgy Malenkov.
- "Boris Nicolaevsky," New America, [New York], vol. 5, no. 17 (March 26, 1966), pg. 2.