Helmut Walcha (1907-1991)
Helmut Walcha was a blind German organist, harpsichordist, and composer who played the works of Dutch and German Baroque masters. He is best known for his recordings of the complete organ works of J.S. Bach. Walcha learned music by hearing his wife or someone else play the notes. He then memorized what he heard and worked on it until he could play it and sing each part. He taught his students that to truly know music you have to be able to not only play it but also sing it.
Helmut Walcha composed and published 4 volumes of chorale preludes for the organ (and arrangements of orchestral pieces or organ pieces.) Here is a recording of two Christmas chorale preludes by Helmut Walcha:
Zu Bethlehem geboren (Born in Bethlehem), and Den die Hirten lobten sehre (Whom the Shepherds Praised Dearly) played by organist Wolfgang Rübsam.