In the early hours of New Year's Eve 1969, in the small soft coal mining borough of Clarksville, Pennsylvania, longtime trade union insider Joseph "Jock" Yablonski and his wife and daughter were brutally murdered in their old stone farmhouse. Seven months earlier, Yablonski had announced his campaign to oust the corrupt president of the United Mine Workers of America (UMWA), Tony Boyle, who had long embezzled UMWA funds, silenced intra-union dissent, and served the interests of Big Coal companies. Yablonski wanted to return the union to the coal miners it was supposed to represent and restore the organization to what it had once been, a powerful force for social good. Boyle was enraged about his opponent's bid to take over―and would go to any lengths to maintain power. The most infamous crimes in the history of American labor unions, the Yablonski murders triggered one of the most intensive and successful manhunts in FBI history―and also led to the first successful rank-and-file takeover of a major labor union in modern U.S. history, one that inspired workers in other labor unions to rise up and challenge their own entrenched, out-of-touch leaders.

Mark A. Bradley has been a US Department of Justice lawyer, a criminal defense lawyer, and a CIA intelligence officer. Currently the director of the Information Security Oversight Office of the National Archives and Records Administration, he lives in Arlington, Virginia.