The more I think about it, the more clear it becomes to me that "LOTR" is the ultimate epitome of the postmodernist novel. Whereas other authors consider the stylistic as a sort of literary game, taking the ideas half-seriously, Tolkien drives the ideas of postmodernist literature to the extreme logical conclusion. "LOTR" to me is a concentrated postmodernist book, what you get when you strip out everything not related to the postmodernist ideal.
For example, if you take a look some other acknowledged postmodernist classics, like Pavicz[1], you see almost the same style of discourse. In fact, it would be very interesting if someone did a comparative analysis of Tolkien and Pavicz.
[1] Word of warning: I've a pretty sketchy knowledge of Pavicz. I know that, judging by current fashions, that firmly places me in the very bottom of the social ladder as far as literature is concerned; please don't hold it against me. Really, I'm not as dumb as I look!