René Leibowitz (French: [ʁəne lɛbɔwits]; 17 February 1913 – 29 August 1972) was a Polish, later naturalized French, composer, conductor, music theorist and teacher born in Warsaw, Poland. He was historically significant in promoting serialism and the New Music in Paris, France after World War II.
Leibowitz studied violin from the age of five, and had begun composing by the age of eight. Between 1921 and 1926 he gave violin recitals in Warsaw, Prague, Vienna and Berlin, but his father then interrupted his performing career, wishing him to have a more normal life. However the boy continued with daily practice, and he began to conduct while a young student in Berlin. It was after hearing a performance of Arnold Schoenberg's Pierrot Lunaire that he resolved to become a composer.
During the early 1930s, Leibowitz studied composition and orchestration with Maurice Ravel in Paris, where he was introduced to Arnold Schoenberg's twelve-note technique by the German pianist and composer Erich Itor Kahn. (Despite his own assertions, Leibowitz did not study with either Schoenberg or Anton Webern). Many of the works of the Second Viennese School were first heard in France at the International Festival of Chamber Music established by Leibowitz in Paris in 1947. Leibowitz was highly influential in establishing the reputation of the School, both through teaching in Paris after World War II and through his book Schoenberg et son école, published in 1947 and translated by Dika Newlin as Schoenberg and his School (US and UK editions 1949). The book was among the earliest theoretical treatises on Schoenberg's 12-tone method of composition, wherein Leibowitz (and Humphrey Searle) were among the first theorists to coin the term "serialism". Leibowitz's advocacy of the Schoenberg school was taken further by two of his pupils, Pierre Boulez and Jacques-Louis Monod, each taking different paths in promoting the music of Schoenberg, Webern and the development of serialism. His American students included the composers Will Ogdon and Janet Maguire, the conductor David Montgomery, and the avant-garde film director-animator John Whitney.