On September 17, 1961, Dag Hammarskjöld boarded a Douglas DC6 propeller plane on the sweltering tarmac of the airport in Leopoldville, the capital of the Congo. Hours later, he would be found dead in an African jungle with an ace of spades playing card placed on his body.

Hammarskjöld had been the head of the United Nations for nine years. He was legendary for his dedication to peace on earth. But dark forces circled him: Powerful and connected groups from an array of nations and organizations--including the CIA, the KGB, underground militant groups, business tycoons, and others--were determined to see Hammarskjöld fail.

A riveting work of investigative journalism based on never-before-seen evidence, recently revealed firsthand accounts, and groundbreaking new interviews, The Golden Thread reveals the truth behind one of the great murder mysteries of the Cold War.