Middle-earth
Another example is C. S. Lewis's "Space Trilogy," in which Earth is also called Middle-earth. Lewis's novels are situated at the approximate time of World War II, with the last novel, "That Hideous Strength," taking place in post-war England, and they specifically bring in references to Tolkien's legendarium (at that time largely unpublished) and treats these references as primary fact within Lewis's fiction. Merlin, of King Arthur fame, is treated as a successor to the Atlantis magic found within "Numinor" (Lewis's unintentional misspelling of Númenor), and similarities can also be found in the Quenya name for Númenor, which is "Atalantë," and Lewis specifically references the earth as Middle-earth twice, both in Chapter 13, "They Have Pulled Down Deep Heaven on Their Heads". Lewis's borrowings came directly from Tolkien himself: they were close friends and shared each other's literary creations. Lewis encouraged Tolkien to persevere with his Middle-earth writings.A small selection from the many books about Tolkien and his created world:
Of Other Worlds
Of Other Worlds is a 1966 anthology of literary criticism by C. S. Lewis and published posthumously by the executors of his estate. It was edited by Lewis' secretary and eventual literary executor Walter Hooper. The first part of the anthology consists of several essays that cover Lewis' ideas about the creation of science fiction or fantasy literature. "Unreal Estates" is the transcript of a recorded conversation between Lewis and the authors Brian Aldiss and Kingsley Amis that took place in Lewis' rooms in Magdalene College "a short while before illness forced him to retire." The second part of the book is made up of three of Lewis' science fiction stories (one of which was previously unpublished) and the beginnings of "After Ten Years", an unfinished novel set during the aftermath of the Trojan War.