True touchstones

"The Art of Fugue" is, quite bluntly put, a collection of compositions on a theme whose possibilities are systematically explored. Here, Johann Sebastian Bach not only employs various types of fugues (simple fugue, counter-fugue, double fugue, triple fugue, mirror fugue, canon) and their traditional forms (inversion, augmentation, and reduction), but also other, more general musical means. Under Bach's hands, the project of a practical teaching t...