Agatha Christie was doing a lot of writing when England was being bombed in World War II. She wrote the final stories for the characters of Miss Marple and Hercule Poirot in case she didn’t survive the Blitz. She wanted to be the one to finish her characters’ story arcs; she didn’t want to leave that important task to a literary executor. The manuscripts, Sleeping Murder (Miss Marple) and Curtain (Poirot) were locked in a bank vault as soon as she finished them, and stayed there nearly until her death in 1976. Curtain was published in 1975, just months before she passed.