The French composer Olivier Messiaen (1908-1992) is one of the pioneers of modern music. Central themes of the Christian faith resonate clearly in his work. Wolfgang W. Müller offers a theological insight into Messiaen's music. He demonstrates how the independence of music as theology points to the transcendent. Perceptible only as fragmented, music in its meaningful dimension aims at the theological. This fundamental aspect has not been sufficiently considered by theology so far. Therefore, Wolfgang Müller provides a sketch for music as a source of theological knowledge in his engagement with the theological themes in Messiaen's music.