This biography of the famous Soviet physicist Leonid Isaakovich Mandelstam (1889-1944), who became a Professor at Moscow State University in 1925, describes his contributions to both physics and technology, as well as discussing the scientific community which formed around him, usually called the Mandelstam school. Mandelstam's life story is thereby placed in its proper cultural context. The following more general issues are taken under consideration: the impact of German scientific culture on Russian science; the problems and fates of Russian intellectuals during the revolutionary and post-revolutionary years; the formation of the Soviet Academy of Sciences; and transformation of the system of higher education in the USSR during the 1920's and 1930's.The author shows that Mandelstam's fundamental writings and his lectures notes allow to reconstruct his philosophy of science and his approach to the social and ethical functions of science and science education. That reconstruction is enhanced through extensive use of hitherto unpublished archival material as well as the transcripts of personal interviews conducted by the author.