Bop began with Jazz but one afternoon somewhere on a sidewalk maybe 1939, 1940, Dizzy Gillespie or Charlie Parker or Thelonious Monk was walking past a men's clothing store on 42nd Street or South Main in L.A. and from a loudspeaker they suddenly heard a wild impossible mistake in jazz that could only have been heard inside their own imaginary head, and that is a new art. Bop.
The portable Jack Kerouac (ed. Penguin Group USA, 1995)