The title, Celestial Blue, is a reference to wide open blue sky and all the possibilities that implies. This release is a culmination of Mark Fewer and Daniel Janke's desire to explore a musical connection through a series of duets, representing their unique voices together. Many songs on the album contain strong references to gospel and folk traditions, music that resonates deeply for Fewer and Janke. Most of the music is through-composed however there are elements throughout of improvisation or comprovisation.