ALASTOR, in early Greek mythology, the spirit of revenge, that prompts the members of a family to commit fresh crimes to obtain satisfaction. Further acts of vengeance trans mit the curse from generation to generation. The word is also used for a man's evil genius which drives him to sin; a man so driven is sometimes called Alastor. The epithet is applied to the Furies (Erinyes) as the deities of revenge, and to Zeus when he is invoked as the "Avenger."