I have been musing about the validity of the book The Hobbit. What an extremely intriguing
book, and how easy to read. The book incorporates the motiffs and
descriptions of underground worlds and their occupants; it is almost
instructional in this regard. For example, it passes on to us that that trolls can't bear the sun,
that goblins and dwarves engage in mining activities, and another good one
is the hidden stone doors along the sides of mountains.
This last one reminds me of the stone door or gate the the children who followed the Pied Piper of Hamlin passd through.
The Hobbit is worth reading.