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place in post-war England, and they specifically bring in references to Tolkien's legendarium (at that time largely unpublished) and treats these references as primary fact within Lewis's fiction.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:
C. S. Lewis
Lewis's interest in the works of George MacDonald was part of what turned him from atheism. This can be seen particularly well through this passage in Lewis's "The Great Divorce", chapter nine, when the semi-autobiographical main character meets MacDonald in Heaven:
He eventually returned to Christianity, having been influenced by arguments with his Oxford colleague and Christian friend J. R. R. Tolkien, whom he seems to have met for the first time on 11 May 1926, and the book "The Everlasting Man" by G. K. Chesterton. Lewis vigorously resisted conversion, noting that he was brought into Christianity like a prodigal, "kicking, struggling, resentful, and darting his eyes in every direction for a chance to escape". He described his last struggle in "Surprised by Joy":