A leading figure in the twentieth-century avant-garde, John Cage was a prolific composer, writer, and artist. His early works show Schoenberg’s influence in their use of a naive modification of the latter’s twelve-tone system. By the late 1930s Cage had begun to pursue his own compositional interests, embarking on a career as a musical innovator who, for fifty years, would send ‘shock waves’ throughout the music world. In ‘The Future of Music Credo’, a manifesto written in 1940, Cage declared that in the future the distinction between ‘noise’ and so-called ‘musical sounds’ would no longer exist.