If you took a confrontation between worlds, such as you might find in a science-fiction novel, and could somehow fold or compress it to fit into the interior space of a normal-sized house, what would you have? Perhaps you would have Julio Cortázar’s “House Taken Over,” from End of the Game (Final del juego, 1956), in which supernatural beings occupy the rear of a normal suburban house, forcing its middle-class, middle-aged inhabitants, a brother and sister, to retreat to the front half and seal off the back half behind a stout oak door: “another world’s intrusion into this one.” Or you might have Carlos Fuentes’s “Aura” (1962), in which a young historian takes up residence in a Mexico City apartment occupied by an aged woman and her double, the “ghost” of her younger self: this world’s intrusion into the other world. Or you might have Cortázar’s “Bestiary” (from Bestiavio, 1951), or its slapstick version, “The Tiger Lodgers” (from Cronopios y famas, 1962), or Richard Brautigan’s “gothic western,” The Hawkline Monster (1974), another slapstick version, or Mikhail Bulgakov’s The Master and Margarita (begun, 1928; completed, 1940) or Cortázar’s 62; Modelo para armar (62: A Model-Kit) (1968), not a house but a city taken over; and so on. Whatever the example, the ontological structure of the projected world is essentially the same in every case: a dual ontology, on one side our world of the normal and everyday, on the other side the next-door world of the paranormal or supernatural, and running between them the contested boundary separating the two worlds-Cortázar’s stout oak door.