Well he wasn't exactly an entirely original author and was just pilfering from his studies of ancient mythology but his books are more readable than the original sources due to being written in a style closer to contemporary english and not suffering from a reverence to original text that you get in most religious books (be it the bible or shakespeare).
Though I still reckon the silmarillion could do with the entire first section being removed.
For a direct pilfering of irish, finnish and english mythology see the incompleat enchanter where the main protagonist uses predicate logic equations to throw himself and a few others into the worlds of the epics (which is of course a comedy novel and does include the Faerie Queen which is just an unreadable epic poem of mock arthurian nature)