[akomtu]

Pretty much all our mythology and fairy tales, including the Tolkien's world, Harry Potter and many movies are based on what I'd call the "occult records". Those records were made partially public at least two centuries before Tolkien was born, so it can't be a coincidence that so many elements of his world match 1:1 with those records. Whether those records are true is a separate question.

Using occult chronology, Tolkien's world corresponds to the Atlantis period (the same Atlantis described by Plato). Tolkien took most of the interesting bits from different epochs and compressed them into one short story. The tall people (2x taller than us) in his story are the atlanteans, Saruman and Gendalf must be Narad and Asuramaya and orcs are creatures made by the evil faction during the late Atlantis when the civilization was on decline. The records say, though, that the bad guys won at the end and the atmosphere during that final chapter was shown in the Prometheus movie. All movies and books, though, present a rosy version of orcs and other evil stuff from the records - an accurate picture would be unthinkable even in the book format.

[Bayart]

You're looking for far-fetched explanations where his academic track record, most notably on Beowulf, provides a completely natural meta-mythological basis for his works.

[wolverine876]

Tolkien, in addition to being the great fantasy writer of the 20th century, he was also an Oxford professor and the century's great scholar of Old English. And in his domain were the myths of northern and central Europe.

He needed no popular book of the occult; he had read all the original myths in their original ancient languages. There is plenty of scholarly work describing his sources, and he wrote his own essay on it, though it's more conceptual than about primary sources: On Fairy-stories.

[fogihujy]

There's definitely a lot of more modern developments as well, but there's also stories like Jack and the Beanstalk, that can be traced back thousands of years and which has themes similar to those described in the article.