He composed music and wrote books which he printed himself. He was very good at writing poetry and other types of books. His theories about rhythm and musical phrasing were ahead of his time. In 1803-06 he published his most notorious work Cours complet d'harmonie et de composition, d'après une théorie neuve et générale de la musique (in 3 volumes). It features among others a new theory about the significance of the upbeat over the downbeat, which was later taken up by Hugo Riemann. Stressing the upbeat instead of the downbeat as commonly taught, gives a jazzlike and fluid quality to all music. This upbeat-phrasing is one of the main characteristics of Jazz but a few classical interpreters use it as well.