Shows how mid-Victorian efforts to gather information about the Fenians laid the foundation for later British domestic intelligence in both Ireland and mainland Britain. British Intelligence and the Fenians provides the first narrative account of the sustained and systematic use of espionage and secret policing in response to Fenianism between 1855 and 1880. It shows that despite the absence of a formal separate political police force or permanent intelligence agency, the British administration in Ireland created a sophisticated intelligence network to combat the revolutionary threat posed by the Fenian Brotherhood in America and the Irish Republican Brotherhood in Britain. The hub of this intelligence network was the Irish administration's "F. Department", which analysed thousands of reports about Fenianism from throughout Great Britain, North America, and continental Europe. Authorities also established a corresponding "separate and secret organization" in London. Such arrangement provided both Irish and English officials ready access to shared intelligence about Fenianism until the end of the 1870s. However, government's agents never managed to infiltrate the leadership of the Fenian organization in Ireland. Such failure left Ireland's rulers uncertain about Fenian intentions and prone to resort to extra-legal measures in response to perceived threats. The book makes an invaluable contribution to our understanding of early political policing and espionage in Britain. By examining in detail what information was collected, how it was analysed and disseminated, and the use policy makers made of it, it more generally offers an interpretation of the role of intelligence in governing Ireland. PADRAIC C. KENNEDY is Associate Professor at the Department of History and Political Science, York College of Pennsylvania.