It has been several years since I read an earlier paperback edition of this classic and my copy is in storage, so this from memory. Robison, a Scottish professor, wrote to warn Britain and other kingdoms that the forces which toppled the French monarchy and started The Terror were still active. He traced the story of the 1776 founding of the Illuminati by Adam Weishaupt a professor at Ingolstadt and the suppression of the order by the royal and church authorities of Bavaria in 1785. The Illuminists went underground all over Europe and used existing Masonic lodges or set up their own as a cover for their activities. In Paris, the Duc d'Orleans headed the Illuminist front called the Grand Orient Lodge, his base to conspire against the ruling House of Bourbon. The English and Scottish lodges were generally apolitical amd many worked actively to keep out Illuminists as insincere applicants, but Robison maintained that some continental lodges remained hotbeds of revolutionary plotting, and therefore dangerous, at the time he wrote.