The episode of the opportunistic valet of Britain's ambassador to neutral Turkey during World War II--dubbed Cicero for the eloquence of the top-secret material he appropriated from his employer Sir Hughe Knatchbull-Hugessen and sold to the Nazis--is a staple of intelligence lore. Yet this remarkable and sometimes comical story has often been recounted with little regard for the facts, most prominently in the popular film Five Fingers. Now, historian and former intelligence officer Richard Wires presents the first full and objective account of the Cicero spy episode, offering...