Despite Messiaen's position as one of the greatest technical innovators of the twentieth century, his musical language has not been comprehensively defined and investigated. The composer's 1944 theoretical study, The Technique of My Musical Language, expounds only its initial stages, and while his posthumously published TraitA(c) de rythme, de couleur, et d'ornithologie contains detailed explanations of selected techniques, in most cases the reader is left to define these more precisely by observing them in the context of Messiaen's analyses of his own works. Technical processes are...