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place in post-war England, and they specifically bring in references to Tolkien's legendarium (at that time largely unpublished) and treats these references as primary fact within Lewis's fiction.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:
Themes of The Lord of the Rings
Since the publications of J. R. R. Tolkien's "The Lord of the Rings", "The Hobbit" and "The Silmarillion", a wealth of secondary literature has been published discussing the literary themes and archetypes present in the stories. Tolkien also wrote about the themes of his books in letters to friends, family and fans, and often within the books themselves. In his Foreword to the Second Edition of "The Lord of the Rings", Tolkien said that he "disliked allegory in all its forms" (using the word "applicability" instead), and told those claiming the story was a metaphor for World War II to remember that he had lost "all but one" of his close friends in World War I.