(born New York City, 22 November 1925).
He studied at the St. Thomas Choir School (1938-42) and had a career as a horn player, notably at the Met (1945-59). He has taught at Tanglewood (from 1963) and was an innovatory, energetic president of the New England Conservatory (1967-77). He has conducted internationally (notably new music), studied jazz and produced a large output, mostly of orchestral and chamber music, but also opera (including The Visitation, 1966). His works draw on Schönberg, Babbitt, Stravinsky, and jazz.