Venona

This groundbreaking historical study reveals the shocking infiltration of Soviet spies in America—and the top-secret cryptography program that caught them. Only in 1995 did the United States government officially reveal the existence of the super-secret Venona Project. For nearly fifty years American intelligence agents had been decoding thousands of Soviet messages, uncovering an enormous range of espionage activities carried out against the United States during World War II by its own allies.