“If you die, nothing lost; if you live, nothing gained.” Haing Ngor was a survivor of the Khmer Rouge during their rise to control of Cambodia and the subsequent agrarian revolution. As a practising doctor at the time of the overthrow of Norodom Sihanouk, the paternalistic head of state, he became a target for the purges of the new regime, which sought to eradicate the vestiges of Western influence as a means to rebuild the country. Year zero saw the forced depopulation of the major cities, with mass movement into the countryside, where large sections of the population became war slaves working on futile and dangerous projects to reform the land.

When the capital, Phnom Penh, is over-run by the Khmer Rouge, Ngor is forced to abandon a patient …