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place in post-war England, and they specifically bring in references to Tolkien's legendarium (at that time largely unpublished) and treats these references as primary fact within Lewis's fiction.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:
Steven A. Beebe
C. S. Lewis and J.R.R. Tolkien were planning on writing a book on language together in the 1940s, but the book was never published. Beebe discovered the opening pages of the manuscript in the Oxford University Bodleian Library. However, there was no proof that Tolkien worked on the project. Originally, the connection of the notes and draft style manuscript to what is now known as Language and Human Nature was not evident to Beebe. It was some time later that he realized what the notes in the book were indicators of the beginnings of the planned project between Lewis and Tolkien. Beebe relied on the help of other prominent C. S. Lewis scholars who are familiar with Lewis' handwriting to carefully transcribe all of the written words in the manuscript. Beebe teaches a reoccurring summer abroad course at Oxford titled "C.S. Lewis: Chronicles of a Master Communicator" about C. S. Lewis and communication sponsored by the Communication Studies Department at Texas State. In 2016 Beebe discovered an unpublished poem by C.S. Lewis in the Oxford University Bodleian library.