Olivier Messiaen (1908-1992) was a French composer of {{classical music}}.

He was a pianist, organist, composer, and devout Catholic Christian. Religion figured strongly into his compositions; he wrote an opera about Saint Francis of Assisi and a two-hour cycle of twenty piano pieces meant to be contemplations on the infant Jesus. Among music theorists, he's also known for developing and using a set of scales he called "modes of limited transposition", as well as a frequent lack of time signature, which results in anything from irregular, jagged rhythms to something akin to Medieval chant, which was also unmetered. He was also very interested in birdsong; he tried to transcribe bird sounds into musical notation, and wrote instrumental imitations of bird calls into some of his music.

Famous works by Olivier Messiaen include:
* ''Quatuor pour la fin du temps'' ("Quartet for the End of Time", quartet for piano, clarinet, violin, and cello)
* ''Saint François d'Assise'' ("Saint Francis of Assisi", opera)
* ''Turangalîla-Symphonie'' ("Turangalila Symphony", work for large orchestra; the character Turanga Leela from ''{{WesternAnimation/Futurama}}'' is named after this piece)
* ''Vingt regards sur l'enfant Jésus'' ("Twenty Contemplations upon the Infant Jesus", set of piano pieces)

Tropes represented in his work:
* AllThereInTheManual: His work often followed certain special rules of tonality derived from scales he called "modes of limited transposition". Some are relatively obvious (such as the better-known whole-tone and octatonic scales), but for a full explanation, you ought to consult his writings about these modes.
* InHarmonyWithNature: Wrote several works glorifying nature, including "Catalogue des Oiseaux" ("Bird Catalogue") and "Des Canyons Aux Etoiles" ("[Looking] Out of the canyons to the Stars").
* RaisedCatholic: Messiaen was a very devout Catholic. Most of his works are inspired by his faith.
* SignatureStyle: A highly distinctive one, including the use of birdsong as melody, cyclical structures, and massive chords that are also colours.
* {{Synesthesia}}: Many of his own prefaces casually refer to individual motifs and chords as "golden", "purple", "orange" etc. despite the fact that most listeners cannot possibly get the reference (even other synesthetes don't necessarily have the '''same''' associations to the same sound).
* UncommonTime: Messiaen's use of rhythm is extremely complex even as twentieth-century music goes, often based on patterns from Hindu music or palindromic forms ("nonretrogradable rhythms"). As under AllThereInTheManual, he wrote a treatise on rhythm... which is [[DoorStopper seven volumes long]].
* WorldOfSymbolism: Some of his works are like this. The ''Vingt Regards sur l'Enfant Jésus'' features not just titles that are related to various things related to baby Jesus, but extensive annotations throughout the score indicating {{leitmotif}}s and other musical constructions that are meant to represent various concepts, characters, or events.