Marcel Dupré

Marcel Dupré (born Rouen, Normandy, 3 May 1886; died Meudon, near Paris, 30 May 1971), was a leading French organist, composer, and teacher.
Biography.
Marcel Dupré was born to a musical family in Rouen (Normandy, France). His father Albert Dupré was organist at the gothic abbey of St Ouen in Rouen. The young Marcel was a child prodigy. He entered the Paris Conservatoire in 1904, where he studied the piano and organ. He studied organ with Alexandre Guilmant and Louis Vierne, and Charles-Marie Widor. His studies with Widor also included composition. In 1914, Dupré won the Grand Prix de Rome for his cantata, "Psyché". Twelve years later, he became professor of organ at the Paris Conservatoire, serving until 1954.
Among his best-known work were more than 2,000 organ recitals in Europe, the United States, Canada and Australia. In 1920 he played in a series of concerts at the Paris Conservatoire in which he played the complete organ works of Johann Sebastian Bach from memory. 
In 1934 he succeeded Widor as organist at St. Sulpice in Paris, serving until his death.
From 1947 to 1954, he was director of the American Conservatory, which was in the Château de Fontainebleau near Paris. In 1954, Dupré succeeded Claude Delvincourt (who had been killed in a car crash) as director of the Paris Conservatoire, serving until 1956. He died at the age of 85.
His playing.
Dupré's organ recitals often included his own work, as well as those of other composers, especially Bach. In the tradition of Widor and Vierne, his compositions included long works in several movements which he called “symphonies”. When he played in church services he would start by playing composed music which was suitable for the time of year. Then he would improvise, playing complicated fugues, trio sonatas and chorale improvisations. He was so good at improvising that many people thought he had composed the music beforehand.
When playing in concerts he was often given a tune, and then he would immediately make up a large work from that tune. In 1906, when he was still a student, he played for a wedding and two services when the famous Widor was going to be absent. Dupré asked Widor what music he should play. Widor told him to improvise something. Dupré waited for Widor to go out of the church before he started practising, but Widor crept back in and listened to him. He realized that Dupré would manage very well.
His teaching.
Dupré was famous as an organ teacher. He taught two generations of well-known organists including Jehan Alain, Marie-Claire Alain, Pierre Cochereau, Jeanne Demessieux,Jean Guillou, Jean Langlais, and Olivier Messiaen. 
His compositions.
Dupré composed a great deal of organ music. As a young child he got to know Aristide Cavaillé-Coll, the most famous organ builder in France. Cavaillé-Coll had built the organ that Dupré’s father played, so he was used to the sound of modern French organs. Most of Dupré's music for the organ is very difficult to play. It includes the "Three Preludes and Fugues", Op. 7 (1914). Even Widor thought that the Prelude of the third piece was simply impossible to perform. However, Dupré could play it, and many organists after him learned to play it, too. Other notable works of Dupré's include the "Symphonie-Passion", the "Esquisses" and "Évocation", and the "Cortège et Litanie". 
As well as composing lots of music, Dupré prepared study editions of the organ works of Bach, Handel, Mozart, Liszt, Mendelssohn, Schumann, César Franck, and Alexander Glazunov. He also wrote music for people who were learning to play the organ, and books on how to improvise on the organ.
References.
“Marcel Dupré at Saint-Sulpice” – Gerard Brooks: Organist’s Review Aug 1986 p. 161-166