This work investigates the complex musical language and theological underpinnings of French composer Olivier Messiaen. Robert Sherlaw Johnson, a composer and pianist himself, utilizes his technical expertise to analyze Messiaen's unique harmonic structures, rhythmic innovations, and the influence of ornithology on his compositions. The book provides a comprehensive framework for understanding how Messiaen synthesized disparate elements—such as birdsong, Indian rhythms, and Catholic mysticism—into a cohesive avant-garde style.

Experts and musicologists frequently cite this text as a foundational resource for understanding the technical mechanics of Messiaen's compositions. Readers often note the academic density of the prose, which assumes a high level of musical literacy from the audience.