Johannes Kepler’s

THE HARMONY

OF THE WORLD

FIVE BOOKS, OF WHICH:

The First is GEOMETRICAL, On the Origin and demonstrations of the Regular Figures The "Regular Figures" refer to the Platonic solids—geometric shapes like the cube or tetrahedron where every face is the same regular polygon., which constitute Harmonic Proportions.
The Second is ARCHITECTURAL, or from FIGURED GEOMETRY, On the Congruence of Regular Figures in a plane or a solid:
The Third is properly HARMONIC, On the Origin of Harmonic Proportions from Figures; and on the Nature and Differences of things pertaining to song, against the Ancients Kepler refers here to his critiques of ancient Greek music theorists like Aristoxenus and Pythagoras.:
The Fourth is METAPHYSICAL, PSYCHOLOGICAL, and ASTROLOGICAL, On the mental Essence of Harmonies and their types in the World; especially on the Harmony of rays descending from the celestial bodies to the Earth, and its effect on Nature or the sublunary Sublunary: Literally "under the moon." In the science of Kepler's time, this referred to the Earthly realm, which was thought to be subject to change, unlike the "unchanging" heavens. and Human Soul:
The Fifth is ASTRONOMICAL and METAPHYSICAL, On the most perfect Harmonies of the celestial motions, and the origin of Eccentricities Eccentricity: A measure of how much an orbit deviates from a perfect circle. Kepler's discovery that orbits are ellipses is central to this book. from Harmonic proportions.
The Appendix contains a comparison of this Work with Book III of the Harmonics of the famous Claudius Ptolemy, and with the Harmonic speculations of Robert de Fluctibus, called original: "Flud" Fludd, an Oxford Physician, inserted into his work on the Macrocosm and Microcosm The Macrocosm and Microcosm: A traditional theory that the structure of the human being (the little world) mirrors the structure of the universe (the great world)..

NOW ADDED, DUE TO THE KINSHIP OF THE SUBJECT
matter, is a book by the same Author published 23 years ago at Tübingen, titled The Forerunner,
or The Cosmographic Mystery, on the causes of the Number of the Heavens, the Proportion
of their motions, and their Periods, from the five
Regular Solids.

At Linz in Austria,

IN THE YEAR 1619.