In 1953, a group of prisoners of war who had fought against the communist invasion of South Korea were released. They chose - apparently freely - to move to Mao's China. Among those refusing repatriation were twenty-one American GIs. Their decision sparked alarm in the West: why didn't they want to come home? What was going on? Soon, people were saying that the POWs' had been 'brainwashed'. Was this something new or a phenomenon that has been...