This book presents authoritative accounts of the evolution, development and application of Royal Naval radar from its inception in 1935 until the end of World War 2. The accounts are based on the individual authors' contemporary experiences, extensive archival research and discussions with surviving wartime colleagues. An overview is presented of the pioneering work at HM Signal School (later the Admiralty Signal Establishment), followed by descriptions of the main programmes of radar development, associated research, and the problems of installation of the equipment in ships, as well as its operation and maintenance at sea. Tabulations of the characteristics and installations of all wartime Royal Naval radars are provided in the Appendices.