J.S. Bach's chorale settings of modal cantus firmi pose an interesting problem for the modern analyst: What assumptions—modal or tonal—does one bring to the music, and what analytic techniques does one use? Are conventional tonal theories adequate to represent the harmonic techniques used in this repertoire? Are conventional modal theories adequate? Lori Burns explores these questions in her study of Bach's modal chorales extending Schenkerian techniques to create an original theory of modality a theory that entails an analytic methodology and individual analytic readings of chorales based on the Phrygian, Mixolydian, Dorian, and Aeolian modes.