Olivier Eugène Prosper Charles Messiaen (December 1908 – April 1992), one of the major composers of the 20th century, was also an organist and ornithologist. He found birdsong fascinating, notating bird songs worldwide and incorporating his birdsong transcriptions into his music. His compositions are rhythmically complex, using a system he called modes of limited transposition, which he abstracted from the systems of material generated by his early compositions and improvisations.

Messiaen traveled widely and wrote works inspired by diverse influences including Japanese music, the landscape of Bryce Canyon in Utah, the life of St. Francis of Assisi, and gamelan (traditional Indonesian music using primarily percussion instruments). He said he perceived colors when he heard certain musical chords (a phenomenon known as synaesthesia); combinations of these colors were important in his compositional process. For a short period Messiaen experimented with the parametrisation associated with "total serialism", in which field he is often cited as an innovator.

Messiaen was appointed organist at the Église de la Sainte-Trinité, Paris, in 1931, a post he held until his death. He taught at the Paris Conservatoire until his retirement in 1978. Major works include Quatuor pour la fin du Temps ("Quartet for the End of Time"), composed while he was a prisoner of war in 1940 and first performed by Messiaen and fellow prisoners for an audience of inmates and prison guards; Turangalîla-Symphonie (1945), La Transfiguration de Notre Seigneur Jésus-Christ (1969), Des Canyons aux Etoiles (1974), the opera Saint-François d'Assise (1983), most recently performed by Germany’s Staatstheater Darmstadt in 2018; and Éclairs sur l’Au-Delà…, completed in 1991 and premiered six months after his death.

His many distinguished pupils included Iannis Xenakis, George Benjamin, Alexander Goehr, Pierre Boulez, Karlheinz Stockhausen, Myung-whun Chung and Yvonne Loriod, who became his second wife.