Leon Bismark "Bix" Beiderbecke (March 10, 1903 – August 6, 1931) was an American jazz cornetist, jazz pianist, and composer.

With Louis Armstrong and Muggsy Spanier, Beiderbecke was one of the most influential jazz soloists of the 1920s. His turns on "Singin' the Blues" and "I'm Coming, Virginia" (both 1927), in particular, demonstrated an unusual purity of tone and a gift for improvisation. With these two recordings, especially, he helped to invent the jazz ballad style and hinted at what, in the 1950s, would become cool jazz. "In a Mist" (1927), one of a handful of his piano compositions and one of only two he recorded, mixed classical (Impressionist) influences with jazz syncopation.