The late seventeenth and eighteenth centuries are known as the Age of Enlightenment, a time of science and reason. But in this illuminating book, Paul Monod reveals the surprising extent to which Newton, Boyle, Locke, and other giants of rational thought and empiricism also embraced the spiritual, the magical, and the occult. Although public acceptance of occult and magical practices waxed and waned during this period they survived underground, experiencing a considerable revival in the mid-eighteenth century with the rise of new antiestablishment religious denominations. The occult spilled over into politics with the radicalism of the French Revolution and into literature in early Romanticism. Even when official disapproval was at its strongest, the evidence points to a growing audience for occult publications as well as to subversive popular enthusiasm. Ultimately, finds Monod, the occult was not discarded in favor of "reason" but was incorporated into new forms of learning. In that sense, the occult is part of the modern world, not simply a relic of an unenlightened past, and is still with us today.