Charles Arnould Tournemire (1870 – 1939) was a French composer, organist, and accomplished improviser. His compositions include eight symphonies (one of them choral), four operas, twelve chamber works and eighteen piano solos. Today he is almost exclusively remembered for his organ music, especially L’Orgue Mystique, a set of 51 suites of pieces for the liturgical year based upon the chants of the day.

He studied organ with César Franck. From 1898 to 1939, Tournemire served as the organiste titulaire at Franck’s old church, the Basilique Ste-Clotilde in Paris. He was also professor of Chamber Music at the Paris Conservatoire. In 1931 he published a biography of Franck. A year before the biography appeared, Tournemire recorded five organ improvisations, which were later transcribed by Maurice Duruflé from the phonograph recordings. These recordings and most all of his improvisations were often rooted in the music of Gregorian chant.

Book:


In 1936, Éditions Max Eschig published Précis d’éxecution de registration et d’improvisation à l’orgue by Charles Tournemire. Of the 117 pages, only the last 16 are devoted explicitly to the art of improvisation. Much of the text is devoted to philosophy, references to examples in repertoire, with some explanation of forms. Tournemire writes that the most profitable study that one could do is to read each day a sonata of Haydn, Mozart or Beethoven, and then to take the same elements and try to develop them oneself.

Recording:

Charles Tournemire: Complete Recordings

Videos:
*original audio recorded by Tournemire with slide show of pictures for videos

Charles Tournemire – Te Deum – Ste. Clotilde, Paris, France
Charles Tournemire – Fantasie on ‘Ave Maris Stella’ – Ste. Clotilde, Paris, France

I couldn’t find a video or audio online of Tournemire himself playing the other improvisations, but am including performances by other organists below because these have been such influential and well-known improvisations:
Charles Tournemire (Philippe Lefebvre plays) – Victimae paschali laudes – Chartres Cathedral, France