Jazz I regard as an American folk music; not the only one, but a very powerful one which is probably in the blood and feeling of the American people more than any other style of folk music.

"The Relation of Jazz to American Music", in Henry Cowell (ed.) American Composers on American Music (1933); reprinted in Gregory R. Suriano (ed.) Gershwin in His Time (New York: Gramercy, 1998) p. 97.