"A smashing Cold War thriller for the twenty-first century." -- People magazine Recruited in the 1930s, the members of the Cambridge spy ring were the most notorious Soviet spies in history. But what if there were a sixth member of the ring whose identity was never revealed? "A lively thriller...astute...inventive...a notable addition to the accounts of the Cambridge spies." -- The New York Times Book Review Sam Gaddis is a divorced academic in need...