"Under a Blanket of Blue" features a half-chorus trumpet solo from Louis Armstrong on the 1956 Verve album Ella and Louis, his warm, burnished tone lending the Jerry Livingston composition an intimacy that perfectly suits its romantic lyric. The 32-bar AABA form at 99 beats per minute in A-flat major provides a relaxed swing framework for the vocal and instrumental interplay between Armstrong and Ella Fitzgerald. Armstrong's trumpet solo, though brief, contains the rhythmic and melodic DNA of jazz itself, his behind-the-beat phrasing and melodic inventions demonstrating the principles that every jazz musician since has built upon. Fitzgerald's vocal is characteristic of her best work from this period, her intonation flawless and her rhythmic sense impeccable. The song, composed in 1933, belongs to the era when the Great American Songbook was being written, and the performance treats it with the respect its craft deserves. The Oscar Peterson Quartet, with Peterson on piano, Herb Ellis on guitar, Ray Brown on bass, and Buddy Rich on drums, maintains a gentle swing feel that never intrudes upon the vocal proceedings. The album Ella and Louis represents one of the supreme achievements in recorded jazz, and this track contributes to its sustained mood of warmth and musical generosity.
