Bandleader and pianist Duke Ellington wrote the jaunty swing piece “In a Mellow Tone” (sometimes displayed as “In a Mellotone”) in 1939, but the song wasn’t officially recorded until this day (September 5) in 1940. A riff on the jazz-age dance tune “Rose Room,” the composition featured a syncopated rhythm and buzzy rhythmic drive that made it a favorite among Swing Era audiences looking to cut a rug. It’s now considered a standard and one of the most popular compositions in jazz. A version of the tune from Duke’s 1959 Columbia album Blues In Orbit — presented here as our Song of the Day — even became the theme song for the Howard Stern Show in the late ’80s and early ’90s.