This book is the first biography in 42 years of the priest and educator whom historians have called “the most important anticommunist in the country.” Edmund A. Walsh, as dean of Georgetown College and founder in 1919 of its School of Foreign Service, is one of the most influential Catholic figures of the 20th century. Soon after the birth of the Bolshevik state, he directed the Papal Relief Mission in the Soviet Union, starting a lifelong immersion in Soviet and Communist affairs. He also established a Jesuit college in Baghdad, and served as a consultant to the Nuremberg War Crimes Tribunal. A pioneer in the new science of geopolitics, Walsh became one of Truman’s most trusted advisers on Soviet strategy. He wrote four books, dozens of articles, and gave thousands of speeches on the moral and political threat of Soviet Communism in America. Although he died in 1956, Walsh left an indelible imprint on the ideology and practical politics of Cold War Washington, moving easily outside the traditional boundaries of American Catholic life and becoming, in the words of one historian, “practically an institution by himself.” Few priests, indeed few Catholics, played so large a role in shaping American foreign policy in the 20th century.