It's a pity that this book is so much "underground"...

[Peter_20]

I dunno how to describe this more accurately, but in this case "underground" means "unknown".
Most people seem to associate Tolkien with Rings of Power and stuff, and they seem to think of Gandalf as a cool wizard running around; they usually don't know that he's also known as Olórin, and came from over the sea with four other wizards: Curumo, Aiwendil, Morinehtar and Rómestámo.
However, I very rarely meet someone who actually knows of people like Fëanor, Fingolfin, Thingol, Túrin and all the other strong characters.
They all seem so... natural, somehow.
I find it really frustrating that the events in The Silmarillion are so unknown; the great battles of Beleriand, the story of the Sun and Moon, and the fall of Gondolin have got to be some of the most fantastic stories ever written - and then almost nobody knows about them!
I've tried to describe parts of the book to people, but either they find it too hard to understand, or else they find it interesting but can't stand the hard-to-read book instead.
And you can't just make a movie about it either, because this movie would go on for at least 30 hours, at least if you include everything in the book.

I always thought of LOTR as a very small part of Tolkien's full story, a part that was easy enough to be accepted mainstream as well.
Not everybody can appreciate stories of how the world was created through music, or how the Sun and Moon were created from a fruit and a flower: you either find them adorable or weird.