Johannes Kepler’s

MATHEMATICIAN,

DEFENSE OF HIS WORK,

THE HARMONY

OF THE WORLD. original: "Harmonices Mundi." This refers to Kepler's 1619 masterpiece where he described his third law of planetary motion and the musical-mathematical ratios of the heavens.

AGAINST THE ANALYTICAL DEMONSTRA-

tion of the Most Illustrious Robert Fludd, original: "Roberti de Fluctibus." Fludd (1574–1637) was a prominent English physician and occult philosopher. He and Kepler famously debated whether the universe's harmony was based on mathematical measurements or mystical, alchemical symbols.

Physician of Oxford.

IN WHICH HE CLAIMS TO BE RESPONDING

to the Appendix of the aforementioned Work. Kepler had included an appendix in "The Harmony of the World" specifically criticizing Fludd's methods; this "Apologia" is Kepler's rebuttal to Fludd's subsequent reply.

An ornate woodcut printer's device. In the center, a staff topped with a crossbar (resembling an anchor or a caduceus) rises from a terrestrial globe showing grid lines. A serpent is entwined around the staff, which is flanked by two leafy branches. This central image is contained within an oval band inscribed with the motto: "GLORY ACQUIRED THROUGH LABOR IS IMMORTAL." original: "IMMORTALIS. LABORE PARTA GLORIA." The entire device is set within a rectangular frame of elaborate Renaissance-style scrollwork, foliage, and two figures at the top corners.

FRANKFURT

At the expense of GOTTFRIED TAMPACH.

IN THE YEAR 1622.

Blue oval library stamp ROYAL LIBRARY original: "BIBLIOTH. REGIA"