Something rare in the study of a period or a subject: a genuinely substantial addition to knowledge, of a kind that will henceforth need to be taken fully into account in any study of the British conduct of the great French Revolutionary and Napoleonic Wars. JOHN EHRMAN A tour de force of research, an essential document for future students of the subject. JOHN LE CARRÉ Elizabeth Sparrow traces the origins of the British secret service to the turbulent aftermath of the French revolution, when Pitt's government, concerned to forestall civil unrest in England, set uppolice surveillance to counteract immigration and sedition. Close study of hitherto unknown Aliens Office documents reveals the expansion of this activity into a foreign secret service, the world of the Scarlet Pimpernel, drawing on an international intelligentsia to infiltrate the French revolutionary government and subsequently, as his domination of Europe seemed ever more certain, Napoleon's military machine. ELIZABETH SPARROW is an independent scholar, author of a number of articles on the early history of the British secret service.