For Olivier Messiaen, music was a way of expressing his faith. He considered it his good fortune to have been born a Catholic and declared that 'the illumination of the theological truths of the Catholic faith is the first aspect of my work, the noblest and no doubt the most useful'. Messiaen is one of the most widely performed and recorded composers of the twentieth-century and his popularity is increasing, but the theological component of his music has so far been neglected and continues to provide a serious impediment for some of his audience. Messiaen the Theologian makes a significant contribution by providing cultural and historical context to Messiaen's theology.An array of international Messiaen scholars cover a wide variety of topics including Messiaen's personal spirituality, the context of Catholicism in France in the twentieth century, and comparisons of Messiaen with other artists such as Dante and Maritain.