RÉTI, RUDOLF (1885–1957), musical theorist and composer. Reti was born in Uzhitse, Serbia, studied at the Vienna Conservatory, and was later a music critic in Vienna. He was one of the founders of the International Society for Contemporary Music (Salzburg, 1922). After emigrating to the United States in 1938, he wrote The Thematic Process in Music (1951) and Tonality, Atonality, Pantonality (published posthumously, 1958), two of the century's most important studies in the genesis and processes of musical composition. Reti's own works include the opera Ivan and the Drum (so far unperformed), a piano concerto, piano pieces, and songs.