J. R. R. Tolkien,

in his writings has created Middle-Earth,

and as you might expect fans have written about this mythical place, but one has made an entire online encyclopedia of the inner world, Tolkien scholar Mark Fisher has created concerning the works of J.R.R. Tolkien - The Encyclopedia of Arda, this site is comprehensive in its coverage of Tolkien's fantasy world of Middle-Earth; no topic is too obscure and no detail is too small, it is an immense reference and repository of knowledge that should interest any devotee of Tolkien's works, I was amazed at the length and breadth of just one of the many categories, titled Old and Rare Words, so if there is anything you want to know about Middle-Earth you will find it here.