This collection of Stephen Clucas's articles addresses the complex interactions between religion, natural philosophy and magic in sixteenth- and seventeenth-century Europe. The essays on the Elizabethan mathematician and magus John Dee show that the angelic conversations of John Dee owed a significant debt to medieval magical traditions and how Dee's attempts to communicate with spirits were used to serve specific religious agendas in the mid-seventeenth century. The essays devoted to Giordano Bruno offer a reappraisal of the magical orientation of the Italian philosopher's mnemotechnical and Lullist writings of the 1580s and 90s and show his influence on early seventeenth-century English understandings of memory and intellection. Next come three studies on the atomistic or corpuscularian natural philosophy of the Northumberland and Cavendish circles, arguing that there was a distinct English corpuscularian tradition prior to the Gassendian influence in the 1640s and 50s. Finally, two essays on the seventeenth-century Intelligencer Samuel Hartlib and his correspondents shows how religion alchemy and natural philosophy interacted during the 'Puritan Revolution'.