Langley types with a penchant for history are digging through the 800 pages of The Secret History of MI-6: 1909-1949, the first authorized history of the British Secret Intelligence Service, written by Keith Jeffery. Think the CIA is tight-lipped? MI-6 only admitted its existence publicly in 1994. "I got through 150 pages last night," says one senior spook. "Couldn't put it down." Among the revelations: the average life span for a spy inside Nazi Germany was a paltry three weeks; that the real SIS has never issued a "licence to kill" (sorry, 007); and the Brits aggressively spied on Washington until 1938. Eventually, the CIA and MI-6 closely collaborated, for instance, against the Communist government in Albania in 1948 (though the U.S. government still denies it). MI-6, it turns out, was also wary of sharing too much with the CIA through 1949 because of a propensity for leaks, especially of intelligence about the Soviet Union.