The epic backstory and mythology of Middle Earth. The grandeur and beauty of the language is a little like the King James edition of the Bible - but with much longer sentences. So, its beauty is counterbalanced by its opacity. I did sometimes have to recap to the start of a sentence or paragraph when I lost the train, and of course many of the characters are referred to by two (or more) names, but in the end, it's the majesty, rather than the detail that matters. If you're expecting something like The Hobbit (or even LotR), this will be a surprise.