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.
Miles Davis he accompanied a singer. In 1945, he replaced Dizzy Gillespie in Charlie Parker's quintet. On November 26, Davis participated in several recording sessions as part of Parker's group Reboppers that also involved Gillespie and Max Roach, displaying hints of the style he would become known for. In Parker's song "Now's the Time", Davis played a solo that anticipated cool jazz. He then joined a big band led by Benny Carter, performing in St. Louis and remaining with the band in California. He again played with Parker and Gillespie. In Los Angeles, Parker had a nervous breakdown that put him in