Calder Walton's "Spies" is a riveting history of espionage

In June 1941 Josef Stalin received a warning from the NKVD, the forerunner of the KGB, that a Nazi attack on the Soviet Union was imminent. "You can tell your 'source' in German air force headquarters to go fuck himself,” was the Soviet leader's response. "He's not a 'source', he's a disinformer.” The invasion came a week later. The anecdote is one of many gems unearthed from the archives in "Spies”, a lucid history of the intelligence contest between America, Britain and Russia. The author, Calder Walton, is an accomplished historian, having contributed to the authorised history of MI5, Britain's…