It has long been acknowledged that alchemy, however bizarre its premises, is the fore-runner of modern chemistry, compelling a figure as rational as Sir Isaac Newton. Other aspects of Renaissance thought are harder to assimilate. In his study of five crucial figures of the 15th and 16th centuries, Anthony Grafton aims to demonstrate that astrology, angelology and conjuration were, if not central to the era’s world view, at least hard to extricate from its more respectable concerns.