Morgan, who has written widely praised biographies of Franklin Roosevelt and Winston Churchill, now offers an ambitious, engrossing, and provocative work on the recurring phenomenon of McCarthyism. Morgan broadly defines McCarthyism as the use and abuse of state power and the creation of a climate of fear in order to control and repress the activities of leftist groups. Morgan usually, but not always, takes a balanced approach to his topic; for example, he views the American intervention in the Russian Civil War as the first strike in the century-long struggle against Bolshevism. That is a questionable description of a confused, ill-fated campaign. Morgan is on firmer ground when describing the cynicism and opportunism of J. Edgar Hoover as he exploited fears of communism to enhance his bureaucratic power. Yet Morgan does not minimize the threat posed and the damage done by widespread Soviet espionage. Ironically, he asserts that by the time Joe McCarthy rose to prominence, the worst of the damage had been done, and actual Soviet espionage was on the wane. Given current efforts to expand the government's power to fight terrorism, this is a timely survey sure to provoke controversy.