Charles Arnould Tournemire (22 January 1870 – 3 or 4 November 1939) was a French composer and organist, notable partly for his improvisations, which were often rooted in the music of Gregorian chant. His compositions include eight symphonies (one of them choral), four operas, twelve chamber works and eighteen piano solos; but today he is remembered largely for his organ music, and by far the best known set of pieces from his pen is l'Orgue Mystique.