Kepler's Physical Astronomy is an account of Kepler's reformulation of
astronomy as a physical science, and of his successful use of
(incorrect) physics as a guide in his astronomical discoveries. It
presents the only reliable account of the internal logic of Kepler's
so-called first and second laws, showing how and to what extent Kepler
thought he had derived them from his physical principles. It explains
for the first time Kepler's attempt to use an obscure discovery of Tycho
Brahe to unify and confirm all of his own physical theories. It also
describes the intricate (and neglected) theory which Kepler developed to
account for the additional anomalies needed for the theory of the moon.