He is considered one of the originators of vocalese, which adds lyrics to existing instrumental songs and replaces many instruments with vocalists (such as the big-band arrangements of Duke Ellington and Count Basie).
He is considered one of the originators of vocalese, which is the art form of lyricising pre-existing recordings of songs including the solos. He was the first to lyricise entire big band arrangements (such as the big-band arrangements of Duke Ellington and Count Basie).