Nikolay Sergeyevich Rusanov (Russian: Никола́й Серге́евич Руса́нов; September 16 (28), 1859, Oryol – July 28, 1939, Berne), also known under the pseudonyms of K. Tarasov and N. Kudrin, was a Russian revolutionary who connected the revolutionary populist movement of the 1870s with the revolutionary parties of the early twentieth century, particularly the Russian Socialist-Revolutionary Party (PSR).
Rusanov studied medicine at the Medical and Surgical Academy in St. Petersburg, where he became involved in radical student politics. He supported the populist (narodnik) movement and in 1877 joined the group 'Land and Liberty' (Zemlya i Volya). When the group split in 1879, Rusanov sided with 'The People's Will' (Nardodnaya Volya). This group emphasised urban organisation over rural agitation among the peasants and also endorsed political terrorism as a tactic. The group assassinated Tsar Aleksandr II in 1881. Although Rusanov was not directly involved in the plot, the repression which followed caused him to flee into exile in 1882. He remained in Western Europe, mostly in France and Germany, until 1905.
Rusanov was one of the earliest Russian revolutionaries to be strongly influenced by Marxism, after reading Marx' Das Kapital, The Communist Manifesto and The Civil War in France. He contributed articles to some early Marxist journals and deployed Marx' thesis that the economic 'basis' determines the political 'superstructure' to argue against the Jacobin voluntarism and élitism of Lev Tikhomirov, the leading ideologue of 'The People's Will' in exile. Rusanov also rejected the popular view among narodniki that capitalism had not yet taken firm root in Russia and could still be avoided. These views put him closer to G.V. Plekhanov, the founder of Russian Social-Democracy, than to populism. Nevertheless, he was attracted to 'The People's Will' and later the PSR for its revolutionary élan. He foundin Nikolai Danielson a welcome interpretation of Marxism that did not seem to require a long period of capitalist development.