Cassidy's Run is the story of one of the best-kept secrets of the Cold War--an espionage operation mounted by Washington against the USSR that ran for 23 years. At the highest levels of the government, its code name was Operation Shocker. Lured by a double agent working for the USA, ten Russian spies, including a University of Minnesota professor, his wife & a classic sleeper spy in NYC, were sent by Moscow to penetrate America's secrets. Two FBI agents were killed & secret formulae were passed to the USSR in a dangerous ploy that may have spurred Moscow to create the world's most powerful nerve gas. Cassidy's Run tells this true story for the 1st time, following a trail that leads from DC to Moscow, with detours to Florida, Minnesota & Mexico. Based on documents secret until now & scores of interviews in the USA & USSR, the book reveals that: more than 4500 pages of classified documents, including US nerve gas formulas, were passed to the USSR in exchange for hundreds of thousands of dollars; an Armageddon code: a telephone call to a number in NYC, was to alert the sleeper spy to an impending nuclear attack--a warning he would transmit to the Soviets by radio signal from atop a rock in Central Park; two FBI agents were killed when their plane crashed during surveillance of one of the spies as he headed for the Canadian border; secret drops for microdots were set up by Moscow from NY to Florida to DC. More than a cloak-&-dagger tale, Cassidy's Run is the story of one ordinary man, Sergeant Joe Cassidy, not trained as a spy, who suddenly found himself the FBI's secret weapon in a dangerous clandestine war.