According to The New Penguin Dictionary of Music
, Gunther Schuller is an American composer (formerly horn player), also conductor, and since 1967 president of the New England Conservatory (Boston). Several of his works use jazz performers. Other works include operas and "Museum Piece" for renaissance instruments and orchestra.
Gunther Schuller is listed in these webpages as the one-off composer of Sandpoint Rag