Jon Hassell (March 22, 1937 – June 26, 2021) was an American trumpet player and composer. He was best known for developing the concept of “Fourth World” music, which describes a “unified primitive/futurist sound” combining elements of various world ethnic traditions with modern electronictechniques. The concept was first articulated on Fourth World, Vol. 1: Possible Musics, his 1980 collaboration with Brian Eno.

Born in Tennessee, Hassell studied contemporary classical music in New York and later in Germany under composer Karlheinz Stockhausen. He subsequently worked with minimalist composers Terry Riley (on a 1968 recording of In C) and La Monte Young (as part of his Theatre of Eternal Music group), and studied under Hindustani singer Pandit Pran Nath. His association with Brian Eno in the early 1980s would introduce Hassell to a larger audience. He subsequently worked with musical artists such as Talking Heads, David Sylvian, Farafina, Peter Gabriel, Tears for Fears, Ani DiFranco, Techno Animal, Ry Cooder, Moritz von Oswald, and Carl Craig.

Born in Memphis, Tennessee, United States, Hassell received his master’s degree from the Eastman School of Music in Rochester, New York. During this time he became involved in European serial music, especially the work of Karlheinz Stockhausen, and so after finishing his studies at Eastman, he enrolled in the Cologne Course for New Music (founded and directed by Stockhausen) for two years, where he met Irmin Schmidt and Holger Czukay, who would later go on to form Can .