Intriguing account of an all but forgotten episode in Cold War history, by two leading scholars of the period. In February 1945, acting on a tip, the head of the South Asia division of the Office of Strategic Services, bought a copy of a small-circulation, leftist magazine called Amerasia. In its pages he found a story on British-American political relations in newly liberated Indochina--a story in his own words, taken from a classified State Department report that only a few senior government analysts had access to. When government agents raided Amerasia's New York office, they found an array of official documents, some marked ``Top Secret,'' and a trail of evidence showing that near-amateur spies had infiltrated the government with astonishing ease. Granted access to FBI files, Klehr (Politics/Emory Univ.; The Secret World of American Communism, 1983, etc.) and Radosh (History/Adelphi Univ.; The Rosenberg File, 1983) tell what happened next: Of the journalists and government officials charged with espionage, none was convicted, thanks largely to inept prosecution; only two of the half-dozen defendants were punished at all, and then only for unauthorized possession of federal documents. The case would quietly resound for the next few years, until Joseph McCarthy, ``an obscure first-term Republican senator of little distinction,'' revived it with a vengeance in his crusade to rid America of the Red Menace. McCarthy's campaign, the authors point out, was flawed by zealousness and a disregard for constitutional niceties, but it had a basis in reality, as the Amerasia case showed; as the authors remark, ``not everyone accused of disloyalty or espionage was innocent--regardless of whether the perpetrator could be legally convicted.'' This academic study is uncommon for its liveliness and important for all students of the Cold War at home.