Intelligence is a defining weapon of the geopolitical clash unfolding among the United States, China, and Russia today, with shadow wars using disinformation and the latest technology to create disruption and discord among the superpowers. Historian Calder Walton reviews the history of Cold War espionage, counterintelligence, and covert action to offer insights into the clandestine struggles now being fought between East and West—and where we are heading.