Vsevolod Mikhailovich Eikhenbaum (23 August [O.S. 11 August] 1882 – 18 September 1945), commonly known by his pseudonym Volin, was a Russian anarchist intellectual. He became involved in revolutionary socialist politics during the 1905 Russian Revolution, for which he was forced into exile, where he gravitated towards anarcho-syndicalism.

He returned to Petrograd following the February Revolution of 1917 and propagandised for anarcho-syndicalism in the Russian capital. In the wake of the October Revolution, which he criticised for bringing the Bolsheviks to power, he left for Ukraine, where he became a leading figure in the Makhnovshchina. During this time, he developed a theory of synthesis anarchism, which advocated for collaboration between anarchists of different tendencies, and spearheaded the intellectual development of Ukrainian anarchism, as leader of the Nabat and chair of the third Military Revolutionary Council during the civil war.

After the suppression of the Russian and Ukrainian anarchist movements by the Bolsheviks, Volin went again into exile. In Paris, he became a leading opponent of platformism, which he criticised as authoritarian, and found work as a prolific writer in multiple different languages. He lived out the last years of his life in poverty, evading persecution by the Nazis and the French State, as he was wanted for his Jewish heritage and his anarchist political convictions. He died of tuberculosis shortly after the liberation of France.