Leonid Mandelstam, Russian physicist and academic (b. 1879)

Leonid Isaakovich Mandelstam or Mandelshtam (Belarusian: Леанід Ісаакавіч Мандэльштам; Russian: Леонид Исаакович Мандельштам, IPA: [lʲɪɐˈnʲit ɨsɐˈakəvʲɪtɕ mənʲdʲɪlʲˈʂtam] (listen); 4 May 1879 – 27 November 1944) was a Soviet physicist of Belarusian-Jewish background.