This book is a thorough going treatment of the subject of Harmony. It contradicts Aristotle, who held science back for centuries because of his witting fraud upon the discoveries of Pythagoras, Thales, et al. Aristotle misrepresented the ideas concerning Music, Harmonics, Geometry as well as Astronomy, which Plato described in the Epinomis to be the fount of all knowledge. In this volume, Kepler proves that the pre-Aristotelean hypothesis of a helio-centric universe is correct, and provides the needed data to demonstrate that the planets arrange their orbits around the sun in the manner of a musical scale. Here one can understand the deeper meaning of Harmony, beyond what we hear in music. Kepler seeks out causes, in the musical domain, as well as in the astrophysical domain. Up to the time of this book, no one had solved the puzzle. This book is a work of genius.