John A. Walker Jr. was a Chief Warrant Officer and communications specialist for the US Navy. In 1985, he was arrested for selling classified secrets to the Soviet Union. Upon his arrest it was revealed that he had been acting as a spy from 1968 to 1985 and that his son, brother, ex-wife, and an acquaintance had also participated in the espionage ring. Altogether, their actions constituted one of the most serious security breaches in US history. In...