But this music, The Art of the Fugue, is not organ music. It does not belong to the canon of Bach's works written for performance on the organ. This canon includes his chorale preludes, his many toccatas, fantasies, preludes, variations, and fugues designated by him as organ pieces - an enormous repetoire for the organ. But The Art of the Fugue belongs among what are called Bach's "didactic" works. In them, Bach, the great teatcher of all musicians, shows what can be achieved by a stupendous contrapuntal intelligence working with minimal constraint from the physical demands and limitations of musical instruments; with, perhaps, no concern that they should be playable at all.