'If you want a novel, read history', wrote Guizot, the historian who rose to high political power under the July Monarchy. He might have been speaking about the life of his Italian collaborator and friend Guglielmo Libri, whose exploits from a subject matter of which the author of many a picaresque novel could only dream. Revolution, theft, lofty ideals, passionate friendship, madness or the intrigues of aristocratic academics: the life of Guglielmo Libri provides ample examples of all of these themes. A Florentine count, Libri moved freely in Italian, French and English academic circles and gallant Society. His talents were remarked upon by the greatest minds of the age, and he was able to apply them in the simultaneous pursuit of several successful careers: those of mathematician, journalist, advisor to the French government and authority on the history of science. Libri's lasting fame, however, is primarily based on his theft of huge quantities of books and manuscripts. From an early age, Libri studied the sources of Italian scientific history in manuscripts and early printed books, and became a renowned collector and connoisseur. This interest was to be his undoing. In the 1840s, charged with compiling accurate catalogues of the French provincial libraries, he augmented his own extensive library with purloined volumes of great antiquity and value. Libri's guilt was concusively proven only after his death in 1869. Several attempts have been made at writing Libri's biography, mainly by scholars troubled by the depredations of which their hero was guilty. This biography is the first in which an attempt has been made to do justice to all aspects of Libri's Promethian life. It presents the reader with vivid impressions of the life of the intellectual elite of Italy, France and England during the first half of the nineteenth century and beyond.