Circle of Treason has the advantage of being written by two intelligence professionals [Sandra Grimes and Jeanne Vertefeuille], not by academics or journalists, and thus is an authoritative account of the Soviet sources that were providing the U.S. with invaluable information during the Cold War until [CIA officer Aldrich] Ames betrayed them. Because classified material on operational cases was going to be made public, the CIA took over three years to approve the book's publication. . . . The first half of Circle of Treason focuses on the sources Ames exposed. . . . The second half of the book describes actions that the agency [KGB] took when the agency's Soviet operations started hemorrhaging after June 1985. . . . The authors present themselves as advocates for their heroes, whose stories they felt deserved to be told.