Cantilena expands on the musical territory of Douglas' previous album, Jewel Lake. Most of that album's ensemble returns on Cantilena, including vocalist Jane Grimes, who features on a folk song version of Yeats' poem "The Lake Isle of Innisfree." The album continues Douglas' exploration of Celtic and Moorish musical traditions, as tracks like "Diamond Dance," "Leap!" and "Sacred Wood" reveal. Bassoon plays a more prominent role on Cantilena, especially on "Sacred Wood" and "Elegy." The album ranges from simple to profound, but Douglas continues to challenge himself and his audience with this collection of songs.