Marguerite de la Rocque (c. 1542) was meant to disappear. That’s what her older relative, Sieur de Roberval, intended to happen when he marooned Marguerite on an uninhabited Canadian island. But against all odds, she survived instead.

Barbara Newhall Follet (1914-unknown) was an American child prodigy novelist. She published two books before she was a teenager and wrote poetry as well. When she was in her twenties, she left her house after fighting with her husband and was never seen again.