In 1921, just three years after the end of World War I, Great Britain’s director of Military Intelligence made the astounding statement that General Allenby had won in Palestine because he “knew from his intelligence every disposition and movement of the enemy. Every one of his opponents’ cards was known to him, and he was consequently able to play his own hand with the most perfect assurance. In those circumstances victory was certain.” Sheffy’s precise and far-ranging research pieces together in masterly fashion just how Allenby benefited from such extraordinary information about his foes. In the process, he shows not only how a key military campaign was fought and won, but also how the modern intelligence service took shape in a spontaneous and amorphous fashion. Along the way, Sheffy demonstrates the near-uselessness of human intelligence (spies, travelers, prisoners of war, et al.), dismissing the whole lot with a quote from the time: “What can agents find out about the intentions of Governments that have no notion what their own intentions are?” In contrast, technical means (air reconnaissance, radio interceptions) proved highly valuable. He establishes how the latter gave the British a much better idea of tactics than of grand strategy, and how they paid heavily for their wrong guesses about the latter. Despite their fair share of mistakes, the British intelligence operatives made a very credible start at bringing a “hitherto hidden dimension ... into the forefront of modern warfare.”