This long-awaited English translation of William of Conches"s Dragmaticon Philosophiae now makes available what is arguably the most original and systematic synthesis of western thought concerning the structure of the physical universe as it was understood in the twelfth century.William"s text fills the scientific gap between late antiquity and Newton, and has influenced the thought of countless writers and thinkers. Medievalists, theologians, and scholars working in the fields of philosophy and history of science will welcome this first-ever English translation of the Dramaticon, especially for its sytematic annotations and full references to doctrinal and literary sources.