Ernst Krenek (August 23, 1900 – December 22, 1991) was an Austrian, later American, composer of Czech origin. He explored atonality and other modern styles and wrote a number of books, including Music Here and Now (1939), a study of Johannes Ockeghem (1953), and Horizons Circled: Reflections on my Music (1974). Krenek wrote two pieces using the pseudonym Thornton Winsloe.