Jazz standard and Billy Strayhorn's "Take the 'A' Train" (1941). With the big bands struggling to keep going during World War II, a shift was happening in jazz in favor of smaller groups. Some swing era musicians, such as Louis Jordan, later found popularity in a new kind of music, called "rhythm and blues", that would evolve into rock and roll in the 1950s. Bebop emerged in the early 1940s, with Charlie Parker, Dizzy Gillespie and Thelonious Monk leading the way. It appealed to a more specialized audiences than earlier forms of jazz, with sophisticated harmonies, fast tempos and often virtuoso musicianship.
Charlie Parker with a chicken and the tour bus. In 1942 Parker left McShann's band and played for one year with Earl Hines, whose band included Dizzy Gillespie, who later played with Parker as a duo. This period is virtually undocumented, due to the strike of 1942–1943 by the American Federation of Musicians, during which time few professional recordings were made. Parker joined a group of young musicians, and played in after-hours clubs in Harlem, such as Clark Monroe's Uptown House. These young iconoclasts included Gillespie, pianist Thelonious Monk, guitarist Charlie Christian, and drummer Kenny Clarke. The beboppers' attitude was summed up