John Dee represents many of the vital currents of scientific study in the Elizabethan Renaissance as well as some of its most notable weaknesses. Called by John Aubrey "one of the ornaments of his Age," Dee was an accomplished and influential figure in the fields of mathematics, astronomy, chemistry, geography, navigation, natural philosophy, and mechanics. Yet, while he was an associate, adviser, and tutor to many of the most important figures of his time in learned and political circles, he was also deeply caught up in astrological, alchemical, hermetic, and occult practices, including crystal-gazing and spirit-calling. He developed among his contemporaries a reputation as a sorcerer and conjuror, which did much to harm his reputation, both during his time and to posterity.

Dee declined university positions, choosing instead to maintain himself as an independent scholar and teacher. His published writings, while significant, were not extensive, and his cramped...