U.S. Navy admiral James Stockdale used the novel's title as a code to his wife and the U.S. government to fool his North Vietnamese captors' censors when he wrote as a POW during the Vietnam War. He signaled the torture of American POW's by Communist North Vietnam: "One thinks of Vietnam as a tropical country, but in January the rains came, and there was cold and darkness, even at noon." His wife contacted U.S. Naval Intelligence and Stockdale confirmed in code in other letters that they were being tortured.