The Cold War was the period of conflict, tension and competition between the United States and the Soviet Union and their respective allies from the mid-1940s until the early 1990s. Throughout this period, the rivalry between the two superpowers unfolded in multiple arenas such as military coalitions, ideology, psychology, and espionage, as well as military, industrial, and technological developments, including the space race. In sports, rising tensions between US and USSR led to boycotts of major events. The Cold War generated for both superpowers costly defence spending, a massive conventional and nuclear arms race, and many proxy wars. There was never a direct military engagement between the US and the Soviet Union, but there was half a century of military buildup as well as political battles for support around the world, including significant involvement of allied and satellite nations in local third parties wars. Although the US and the Soviet Union had been allied against Axis powers, the two sides differed on how to reconstruct the postwar world even before the end of World War II. Over the following decades, the Cold War spread outside Europe to every region of the world, as the US sought the "containment" of communism and forged numerous alliances to this end, particularly in Western Europe, the Middle East, and Southeast Asia. This encyclopedia, in a new and updated edition, offers the most comprehensive information on a fascinating and troubling subject. Most spy encyclopedias seek to cover the entire scope of espionage. This book covers in depth a very specific and important moment in espionage history: that of the Cold War and is unique in doing so in such detail.