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.
Jazz include Jackie McLean, and two of the musicians who had also played on "Kind of Blue": John Coltrane and Bill Evans. By the 1950s, Afro-Cuban jazz had been using modes for at least a decade, as much of it borrowed from Cuban popular dance forms which are structured around multiple ostinatos with only a few chords. A case in point is Mario Bauza's "Tanga" (1943), the first Afro-Cuban jazz piece. Machito's Afro-Cubans recorded modal tunes in the 1940s, featuring jazz soloists such as Howard McGhee, Brew Moore, Charlie Parker, and Flip Phillips. However, there is no evidence that Davis or