However deficient by modern standards was the astronomical knowledge of most early astronomers, one never ceases to wonder at the completeness and precision of some of their results, derived as they were from inaccurate observations made with the naked eye or with crude instruments. The main results of astronomy that could be discovered by the naked eye actually were discovered by the best ancient observers. "Planetary Systems from the Ancient Greeks to Kepler" describes the detailed technical models whereby astronomers prior to Newton accounted for their observations. Unlike histories of science that focus on the influence of great ideas, this book presents the actual substance of those ideas and details their elaboration and development. The exposition is as geometrical as possible, reflecting the original style of the ancients. The first chapter presents the general body of observational astronomy known to the ancients and forming the subject of their explanatory endeavors. Each of the following chapters concentrates on the work of a single astronomer - Eudoxus, Hipparchus, Ptolemy, Copernicus, Tycho, and Kepler - and provides biographical details, a detailed exposition of his astronomical system, and some evaluation of the astronomer's role in the history of astronomy. Theodor S. Jacobsen is professor emeritus of astronomy at the University of Washington."
