In 1860, Palmerston’s parliament sanctioned the construction of the largest system of fortifications that the British Isles had ever seen, or would ever see again, in order to defend against a feared French invasion. William Jervois (1821–97), then a young major in the Royal Engineers, was appointed as “design leader” of this program, which later led to a career in fortress construction that spanned continents and empires. This volume is a detailed study of Jervois’s life and works, based on extensive use of extracts from his diary and illustrations of his most important fortresses, offering the reader a rounded picture of his glittering career, as well as the political and technical considerations involved in fort and armament construction.