The first scholarly book on Thomas Vaughan (1621-1666) draws from recent studies in Western esotericism to place his famously difficult writings in their proper context. It shows that they develop themes from a distinctively Rosicrucian synthesis of alchemy, magic, and Christian cabala. Vaughan introduced Rosicrucian documents to English readers and placed them in older philosophical contexts during the breakdown of censorship that followed the English Revolution against the old order in politics and religion. Willard's book will appeal to students of early modern ideas about religion, science, and society as they were seen by an intelligent and eloquent outsider.