One could make a whole catalogue of interesting tidbits from Christopher Tolkien's study - such as the fact that Strider was called Trotter until a very late stage in the writing of the book; that Trotter was at one time a hobbit, so named because he wore wooden shoes; that Tolkien at one point considered a romance between Aragorn and Eowyn; that Tolkien wrote an epilogue to the book, tying up loose ends, but it was dropped before publication (and now appears in Sauron Defeated); and so on.