In recent years, scholars have devoted considerable attention to the role of transparency in international relations. U.S. efforts during the early Cold War to press for greater openness as a way of reducing tensions with the Soviet Union are often cited by specialists on military transparency. Yet the ill-fated Open Skies proposal has not been thoroughly investigated. This article draws on primary documents from the Truman and Eisenhower administrations to show that proponents of transparency have generally drawn the wrong conclusions about Open Skies. The U.S. proposal for a system of aerial observation was part and parcel of a strategy to contain and ultimately defeat the Soviet Union. Consequently, Open Skies does not conform to the logic of transparency as a confidence-building measure; it instead affirms basic realist thinking about the competition for security between rivals. Future scholarship that appreciates how the quest for a more open world is affected by the competition for security would improve our understanding of the causes, consequences, and limitations of transparency.