Few, if any, free jazz saxophonists approached music with the same degree of intellectual rigor as Sam Rivers; just as few have managed to maintain a high level of creativity over a long life. Rivers played with remarkable technical precision and a manifest knowledge of his materials. His sound was hard and extraordinarily well-centered, his articulation sharp, and his command of the tenor saxophone complete. Rivers' playing sometimes had an unremitting seriousness that could be extremely demanding, even off-putting. Nevertheless, the depth of his artistry was considerable. Rivers was as substantial a player as avant-garde jazz ever produced.