Alexander Esenin-Volpin, Russian-American mathematician and poet (b. 1924)
Alexander Sergeyevich Esenin-Volpin (also written Ésénine-Volpine and Yessenin-Volpin in his French and English publications; Russian: Алекса́ндр Серге́евич Есе́нин-Во́льпин; May 12, 1924 – March 16, 2016) was a prominent Russian-American poet and mathematician.

A notable dissident, political prisoner and a leader of the Soviet human rights movement, he spent a total of six years incarcerated and repressed by the Soviet authorities in psikhushkas and exile. In mathematics, he is known for his foundational role in ultrafinitism.