|I'm also a sucker for awesome cover designs|
Mythopoeisis is a subject of great interest for me, personally, and one that Miller handled very well. Not only do we see how the lives and events within the monastic order of St. Leibowitz become mythologized, but we see how something as extreme as nuclear holocaust can be folded into religion:
"It was said that God, in order to test mankind which had become swelled with pride as in the time of Noah, had commanded the wise men of that age, among them the Blessed Leibowitz, to devise great engines of war such as had never before been upon the Earth, weapons of such might that they contained the very fires of Hell, and that God had suffered these magi to place the weapons in the hands of princes, and to say to each prince, "Only because the enemies have such a thing have we devised this for thee, in order that they may know that thou hast it also, and fear to strike. See to it, m'Lord, that thou fearest them as much as they shall now fear thee, that none may unleash this dread thing which we have wrought."
But the princes, putting the words of their wise men to naught, thought each to himself, If I but strike quickly enough, and in secret, I shall destroy those others in their sleep, and there will be none to fight back; the earth shall be mine.
Such was the folly of princes, and there followed the Flame Deluge."
As you could probably guess, religion plays a large role in the story. Like I said, I'm interested in mythopoeisis, so the religious aspect works pretty well in that regard (incidentally, I've just started reading Isaac Asimov's Guide to the Bible, which seems to be an insightful look at much the same subject).
If you're a fan of science fiction, post-apocalyptic stories, or just good original writing, I'd suggest picking up a copy.