Unknown music for me (I have over 2000 CD). I just found a hinge between Mozart and Beethoven. I find it more interesting than the various "tests" Haydn (fortepiano, harpsichord, organ) who have trouble (for my taste) impregnating the memory. Where Chopin sometimes said "Listen as I know to play the piano" Ries seems to say it more simply and key at both the heart. I have listened to two discs 5 and I promise, again, a good few hours of listening. In common place I want to say "A procuring eyes closed and ears open."