Composer, French hornist, educator, jazz scholar; born in New York City. He became first chair of the Metropolitan Opera Orchestra at age 19. He left that post to pursue composition and teach at Yale (1964--66); from 1966 to 1977 he was president of the New England Conservatory; meanwhile he taught at Tanglewood in the summer, and from 1974 to 1984, he directed the music school there. A prolific composer, his mature work uses 12-tone technique often inflected by his involvement in jazz. His prose writings include the classic 1968 study Early Jazz.