The French Revolution and the bloodcurdling violence it engendered terrified the ruling and propertied classes of Europe. Unable to grasp how such horrors could have come about, many concluded that it was the result of a devilish conspiracy hatched by Freemasons inspired by the ideas of the Enlightenment with the aim of overthrowing the entire social order, along with the legal and religious principles it stood on. Others traced it back to the Reformation or the Knights Templar and ascribed even more sinister aims to it. Faced by this apparently occult threat, they resorted to repression on an unprecedented scale, expanding police and spy networks in the process. This compelling history, occasionally chilling and often hilarious, tells how the modern state evolved through the expansion of its organs of control, and holds urgent lessons for today.