Throughout recorded history, human beings have claimed to make contact with supernatural powers from beyond this world. In the Judeo-Christian and Islamic traditions these beings are known as angels. Angels play an enormously important role in these traditions. They help create the first human beings. They reveal sacred scriptures and help found religions. They procreate with women. They transport prophets and seers, like Muhammad or Enoch, through the heavens to receive secret wisdom. And these angels become warriors in the apocalypse, battling demons and helping to create a new earth. Since 1947, a new extra-terrestrial power has appeared in literature, film, comics and religious scripture: the alien. Abductees, artists, and religious v...