On a night nearly 43 years ago, while Muhammad Ali and Joe Frazier bludgeoned each other over 15 rounds in a televised title bout viewed by millions around the world, burglars took a lock pick and a crowbar and broke into a Federal Bureau of Investigation office in a suburb of Philadelphia, making off with nearly every document inside. They were never caught, and the stolen documents that they mailed anonymously to newspaper reporters ... would become a flood of revelations about extensive spying and dirty-tricks operations by the F.B.I. against dissident groups. Perhaps the most damning document from the cache [was] a 1970 memorandum that ... urged agents to step up their interviews of antiwar activists and members of dissident student groups. It will enhance the paranoia endemic in these circles and will further serve to get the point across there is an F.B.I. agent behind every mailbox." Another document, signed by Hoover himself, revealed widespread F.B.I. surveillance of black student groups on college campuses. But the document that would have the biggest impact on reining in the F.B.I.'s domestic spying activities [included] a mysterious word: Cointelpro ... shorthand for Counterintelligence Program. Since 1956, the F.B.I. had carried out an expansive campaign to spy on civil rights leaders, political organizers and suspected Communists, and had tried to sow distrust among protest groups. Among the grim litany of revelations was a blackmail letter F.B.I. agents had sent anonymously to the Rev. Dr. Martin Luther King Jr., threatening to expose his extramarital affairs if he did not commit suicide. The intent of Cointelpro was to destroy lives and ruin reputations.