In 1952, Goodnight Moon (1947) author Margaret Wise Brown was in France on a publicity tour when she developed appendicitis and was taken to the hospital for emergency surgery. To show the staff that she was feeling well after the operation, she kicked her leg in the air—a move that dislodged a blood clot in her leg. The clot made its way to her brain, killing the 42-year-old children’s author.