[A] very excellent order of sounds or pitches in a musical system or scale has been set up by men, since you see that they are doing nothing else in this business except to play the apes of God the Creator and to act out, as it were, a certain drama of the ordination of the celestial movements.
Really a four star book, but I had to subtract a star for an inexcusable lack of explanatory notes. The few that were provided were helpful, but, really, with the spate of obscure terms and confusing concepts in this book, couldn't the editors do better? I have a Bachelor's degree in music, and I still had to look up the obscure terms diesis, lemma, and comma; all of which have to do with just tuning, the system used in Kepler's time but which has now been discarded in favor of even tempered tuning. I could follow the spate of ratios pretty well, but I can't imagine that even a reader reasonably well versed in music could get very far without becoming hopelessly lost. Since this volume contains only book five of Harmonies of the World, Kepler keeps referring back to the previous four volumes of this work. Would it have been too much for the editors to explain these references more fully, to clue in those of us who missed the first four books? I found myself having to take Kepler's word for it that the ratios provided matched his real world observations, but even here I kept getting confused as to whether he was talking about ratios in distance or velocity or both.
Nevertheless, it was neat to see Kepler demonstrate his main contention, which I extracted from p 34 at the beginning of this review. (Even though his argument seems forced to modern ears.) I'm sure that Kepler would be quite disappointed to find that not only have we discarded the "excellent order of sounds or pitches" in use in his time in favor of even temperament, but we have since discovered Uranus and Neptune, which really screws up his system.