The narrator, supposedly Lewis himself, comes in to say that the story itself is now over but there are certain things left to reveal about how this book was written. Dr. Ransom, an alias for an actual professor in England, quickly abandoned his dreams of publishing a Malacandrian dictionary or telling the world of his extraterrestrial adventure. He accepted that this experience must have been a hallucination, and would have stayed quiet for the rest of his life if not for a strange coincidence.
Lewis (the author) ends the book by claiming that all the events of the novel were true, turning himself into a character and explaining away Ransom’s strange name as an alias to protect the “real” identity of some supposedly well-known professor. Notably, the pressure of normal life makes Ransom forget his convictions, as Lewis points out that religious fervor is hard to maintain in modern England.
Lewis explains that he was a student of Dr. Ransom’s, often asking for help with for literary and linguistic questions. A few months ago, Lewis sent Dr. Ransom a letter asking what meaning there might be to the word “oyarses” in an ancient Latin text about a voyage through heaven, in a context that seems to refer to a tutelary (or guardian) spirit. Dr. Ransom then invited Lewis to his home and explained the whole story of his time on Mars.
Lewis again calls back to ancient thought, giving the old mythology just as much credence as the modern pursuits of science and reason. What modern men dismiss as superstition, Lewis holds up as a better understanding of the world. He therefore supports some of the old values of Christianity even if modern England has rejected them altogether.
Lewis agreed not to spread this story as truth, for fear of retaliation by the real “Weston,” but continues to help Dr. Ransom collect evidence from Platonist thinkers to form a resistance for the inevitable time when Weston tries again to colonize Malacandra. Dr. Ransom suggests publishing his account as a fiction, to plant a seed of certain ideas so that when the time comes to reveal the truth about Mars, it will be easier to accept. Lewis tells the reader to look out for the next stages of Dr. Ransom’s adventure.
Lewis describes this fight against Weston as an on-going battle, mirroring the battle that Maleldil fights against the Bent One. (And indeed, Ransom and Weston both return in the sequel, Perelandra.) Ransom’s idea to publish this as fiction also matches Lewis’s (the author) hope to hide his truths of Christian thought in this science fiction novel.