Jazz standards are musical compositions that are widely known, performed, and recorded by jazz artists as part of the genre's musical repertoire. This list includes tunes written in the 1940s that are considered standards by at least one major fake book publication or reference work. The swing era lasted until the mid-1940s, and produced popular tunes such as Duke Ellington's "Cotton Tail" (1940) and Billy Strayhorn's "Take the 'A' Train" (1941). When the big bands struggled to keep going during World War II, a shift was happening in jazz in favor of smaller groups. Some swing era musicians, like 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, led by Charlie Parker, Dizzy Gillespie, Thelonious Monk, and others. It appealed to a more specialized audience than earlier forms of jazz, with sophisticated harmonies, fast tempos, and often virtuoso musicianship. Bebop musicians often used 1930s standards, especially those from Broadway musicals, as part of their repertoire. Among standards written by bebop musicians are Gillespie's "Salt Peanuts" (1941) and "A Night in Tunisia" (1942), Parker's "Anthropology" (1946), "Yardbird Suite" (1946) and "Scrapple from the Apple" (1947), and Monk's "'Round Midnight" (1944), which is currently the most recorded jazz standard composed by a jazz musician. 1940 "After Hours" is a song composed by Avery Parrish with lyrics by Robert Bruce and Buddy Feyne. Parrish's own hit instrumental version, featuring him on piano with the Erskine Hawkins Orchestra, was recorded on June 10, 1940. Lyrics were added later. "All Too Soon" is a jazz ballad composed by Duke Ellington with lyrics by Carl Sigman. Tenor saxophonist Ben Webster's performance on the tune was so highly regarded by audiences that his successors in the band were asked how they dare sit on Webster's seat. Webster later recorded the tune with young Sarah Vaughan in 1946. "Cotton Tail" is a swing jazz composition by Duke Ellington, with lyrics later added by Jon Hendricks. It was based on the Rhythm changes, a chord progression later used as a basis for many bebop tunes. Ben Webster was often asked by audiences to play his famous tenor saxophone solo note for note. The name of the tune is sometimes spelled as "Cottontail". "Do Nothing till You Hear from Me" (a.k.a. "Concerto for Cootie") is a song composed