Olivier Alain was a French pianist, musicologist, and composer, brother of the organist and copmposer Jehan (Ariste) and the renowned organist Marie-Claire Alain. He studied organ and piano in his youth. Then he took courses in composition with Aubin and Messiaen at the Paris Conservatoire.
From 1950 to 1964 Olivier Alain served as director of the Conservatory in St. Germain-en-Laye. In 1961 he was appointed to the faculty of the École César Franck in Paris.
Olivier Alain composed an oratorio, Chant funèbre sur les morts en montagne (1950); also motets and pieces for organ and piano. He published the manual L'Harmonie (Paris, 1965) and the monograph Bach (Paris, 1970). His discovery of Bachs Handexemplar of the Goldberg Variations in Strasbourg in 1974 is often regarded as one of the greatest Bach-source finds of the 20th century.