Gillock supplies details about the organ at La Trinité in Paris, the instrument for which most of Messiaen's pieces were imagined.

Olivier Messiaen: A Research and Information Guide is a unique bibliographical resource that presents the reader with the most significant and helpful resources on Olivier Messiaen, one of the twentieth century's greatest composers, published between 1930 and 2007. An introductory chapter offers a short biography of Messiaen, a consideration of his musical style and works, and a discussion of Messiaen studies. Chapters 2 and 3 concentrate on the primary literature, organized around manuscript collections, articles and reviews, pedagogical works, lectures and librettos, prefaces, interviews, correspondence, and documentaries and filmed performances. Chapters 4 through 9 focus on the secondary literature, namely, biographical and stylistic studies, topical examinations, discussions of particular works, accounts of Messiaen in works devoted to other topics, reviews of books and significant performances of Messiaen's music, and examinations of source materials on the Internet. A list of works and a selected discography conclude the book.

This study draws portraits of the French romantic organist-composers including Aristide Cavaille-Coll, Cesar Franck, Charles-Marie Widor, Louis Vierne, Marcel Dupre, Jean Langlais and Olivier Messiaen. The author details the lives, times, styles, and techniques of these composers.

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.