Sally is a musical comedy with music by Jerome Kern, lyrics by Clifford Grey and book by Guy Bolton, with additional lyrics by Buddy De Sylva, Anne Caldwell and P. G. Wodehouse. The plot hinges on a mistaken identity: Sally, a waif, is a dishwasher at the Alley Inn in New York City. She poses as a famous foreign ballerina and rises to fame through joining the Ziegfeld Follies. There is a rags to riches story, a ballet as a centrepiece, and a wedding as a finale. "Look for the Silver Lining" continues to be one of Kern's most familiar songs. The song is lampooned by another song, "Look for a Sky of Blue," in Rick Besoyan's satirical 1959 musical Little Mary Sunshine.

Musical theatre is a form of theatrical performance that combines songs, spoken dialogue, acting and dance. The story and emotional content of a musical – humor, pathos, love, anger – are communicated through words, music, movement and technical aspects of the entertainment as an integrated whole. Although musical theatre overlaps with other theatrical forms like opera and dance, it may be distinguished by the equal importance given to the music as compared with the dialogue, movement and other elements. Since the early 20th century, musical theatre stage works have generally been called, simply, musicals.