Olivier Messiaen (1908-1992) was a French composer, organist, and ornithologist known for his innovative contributions to 20th-century classical music. He is associated primarily with modern classical music, particularly the post-war avant-garde movement, and his works often incorporate elements of religious mysticism, nature, and the rhythms of birdsong. Notable works include the orchestral piece "Turangalîla-Symphonie" (1946-1948), which blends traditional orchestration with electronic elements, and "Quartet for the End of Time" (1941), composed while he was a prisoner of war, showcasing his unique harmonic language and rhythmic complexity. His "Visions de l'Amen" (1936) for two pianos is another key work that reflects his spiritual and synesthetic experiences. Messiaen's impact on music is profound; he influenced generations of composers with his use of color in harmony, innovative rhythms, and incorporation of non-Western musical ideas and bird calls. His teaching at the Paris Conservatoire shaped the next wave of contemporary composers, including Pierre Boulez and Karlheinz Stockhausen, cementing his legacy as a pivotal figure in 20th-century music.