Hoffman David E. The Billion Dollar Spy

While driving out of the American embassy in Moscow on the evening of February 16, 1978, the chief of the CIA’s Moscow station heard a knock on his car window. A man on the curb handed him an envelope whose contents stunned U.S. intelligence: details of top-secret Soviet research and developments in military technology that were totally unknown to the United States. In the years that followed, the man, Adolf Tolkachev, an engineer in a Soviet military design bureau, used his high-level access to hand over tens of thousands of pages of technical secrets.