Z for Zachariah is a post-apocalyptic science-fiction novel by Robert C. O'Brien that was published posthumously in 1974. The name Robert C. O'Brien was the pen name used by Robert Leslie Conly. After the author's death in March 1973, his wife Sally M. Conly and daughter Jane Leslie Conly completed the work, guided by his notes. Set in the continental territory of the United States, it is written from the first-person perspective as the diary of sixteen-year-old Ann Burden. Burden has survived nuclear war and nerve gas by living in a small valley with a self-contained weather system. According to Sally Conly in summer 1972, Z for Zachariah would be her husband's "second adult novel" following the months-old science-fiction thriller A Report from Group 17. O'Brien had previously established himself as a children's writer with novels The Silver Crown (1968) and Mrs. Frisby and the Rats of NIMH (1971). In the event, Z for Zachariah was a runner-up for the 1976 Jane Addams Children's Book Award and it won the Edgar Award for best mystery fiction in the juvenile category. Plot summary Ann Burden is a teenage girl who believes she is the last survivor of a nuclear war. Since her family's disappearance on a search expedition, she has lived alone on her farm in a small valley spared from radiation poisoning. A year after the war, a stranger in a radiation-proof suit approaches her valley. Afraid he might be dangerous, Ann hides in a cave and does not warn the man when he mistakenly bathes in a radioactive stream. When he falls ill, her fear of being alone forever leads her to reveal herself to help him. She discovers that the stranger is John Loomis, a chemist who helped design a prototype radiation-proof "safe-suit" at an underground lab near Ithaca, New York. Ann moves him into her house and fantasizes about eventually marrying him. Loomis becomes delirious, with traumatic flashbacks to the underground lab. He talks of how he shot his coworker, Edward, who tried to take the safe-suit to find his family. Though troubled by this revelation, Ann nurses him through his illness and keeps secret her knowledge of Edward's death. As Loomis recovers, Ann is taken aback when he forbids her to touch the safe-suit and begins giving her orders on farming and managing resources. His explanation that they have to plan "as if this valley is