The book delves into the historical significance of the deviant psalm-tone, tonus peregrinus, and its use in polyphonic music across Western liturgy. It traces the enduring tradition of this melody from the ninth century to the twenty-first century, exploring how contemporary music theory addresses the challenges it presents to modal and tonal practices throughout different historical periods. Lundberg's investigation reveals the intricate relationship between this psalm-tone and the evolution of musical practices over time.
