Letter of the 99
The letter of the 99 (in Russian: Письмо девяноста девяти) is a collective open letter signed in 1968 by several famous Soviet mathematicians in defense of their colleague Aleksander Yesenin-Volpin, who was forcibly committed to a psychiatric hospital in connection with his dissident activities. The letter became an important event in the history of both Soviet mathematics and the human rights movement.