Jazz Jazz is a type of music developed by black Americans about 1900 and possessing an identifiable history and describable stylistic evolution. It is rooted in the mingled musical traditions of American blacks. More black musicians saw jazz for the first time a profession. Since its beginnings jazz has branched out into so many styles that no single description fits all of them with total accuracy. Performers of jazz improvise within the conventions of their chosen style. Improvisation gave jazz a personalized, individualized, and distinct feel. Most jazz is based on the principle that an infinite number of melodies can fit the co