As Roberts (a Fellow at Merton College, Oxford) makes clear at the outset, this is not a history of secret societies -- Freemasons, Carbonari, Illuminati, Sinn Fein, the Comintern and the rest. Rather, it is an exploration of the genesis and metastasis of a delusion -- the idee fixe that European society was being subverted by a diabolical network of conspiratorial cadres whose members were bound by terrible oaths to the destruction of Property, Religion, Morality and the Family. The myth first appeared in the late 18th century couched in rumors, suspicions and Papal condemnations of Freemasonry -- in actuality an innocuous fraternal organization of middle-class English origins which fulfilled roughly the same social function as the London coffee house. Continental offshoots quickly proliferated along with the first backlash. However it was the French Revolution which shook public consciousness to the core, that really advanced the fiction of secret manipulators to the status of a popular demonology. Roberts goes on to show that the myth soon acquired ""generative powers"" and by the time of Babeuf, Buonarroti and the Conspiracy of Equals, would-be revolutionaries had created and shaped actual organizations to fit the mythical prototype -- now embellished by a wholly fanciful prehistory linking it to the Crusades and the medieval Templars. Throughout the 19th century perfectly sane politicians and statesmen continued to believe in this historical deus ex machina (Disraeli among others warned of plots to ""ravage"" Europe) and both the Bolsheviks and Nazis launched persecutions of masonic lodges. Roberts' scope is Pan-European and he incisively analyzes the social conditions and intellectual climate which gave rise to this plot psychosis, tracing its root to the desperate need of the generation which had experienced the French Revolution to explain ""change on an unprecedented, accelerating and ever-grander scale."" He also makes some suggestive analogies with anti-Semitism which similarly evinced the virulent tenacity of irrationalism in the body politic. A fascinating excursion into an area of ""highly organized nonsense"" hitherto neglected by historians. With obvious contemporary relevance for those interested in the origins of the devil theory of politics.