“I’m Always Chasing Rainbows,” which is based on Chopin’s Fantaisie-Impromptu, Op. 66, was first composed (as it were) in 1918, and it became popular again in the 1930s and ’40s. Eddie Sauter (1914–1981) made this arrangement in 1940 for Benny Goodman’s band. The Gilmore Music Library is now the home of the papers of both Goodman and Sauter. The second page shows a jazzy version of Chopin’s famous melody in the trombones. (The key signature, E-flat major, is indicated only on the first page.)