In these essential articles have been fundamentally revised to incorporate new evidence and information withheld by governments when they were first published. This volume reshapes the study of communications intelligence by tracing Britain's development of cipher machines providing the context to Ultra and Enigma, and by explaining how British and German signals intelligence shaped the desert war. The author also explains how intelligence affected British strategy and diplomacy from 1874 to 1940 and world diplomacy during the 1930s and the Second World War. Finally he traces the roots for contemporary intelligence, and analyzes intelligence and the RMA as well as the role of intelligence in the 2003 Gulf War. This volume ultimately brings new light to our understanding of the relations between intelligence, strategy and diplomacy between the end of the 19th century and the beginning of the 21st century.