Tolkien is a writer of greater theological depth than his Oxford colleague C S Lewis, in my judgment. Lewis is a felicitous writer and a diligent apologist, but mere allegory along the lines of the Narnia series can do no more than restate Christian doctrine; it cannot really expand our experience of it. Tolkien takes us to the dark frontier of a world that is not yet Christian, and therefore is tragic, but has the capacity to become Christian. It is the world of the Dark Ages, in which barbarians first encounter the light. It is not fantasy, but rather a distillation of the spiritual history of the West. Whereas C S Lewis tries to make us comfortable in what we already believe by dressing up the story as a children's masquerade, Tolkien makes us profoundly uncomfortable. Our people, our culture, our language, our toehold upon this shifting and uncertain Earth are no more secure than those of a thousand extinct tribes of the Dark Ages; and a greater hope than that of the work of our hands and the hone of our swords must avail us.
I don't think one has to buy into the author's dismissal of Lewis here to appreciate, on the other hand, the points he is making about Tolkien's work.
