This book is available here.
I haven't read a lot of science fiction – I will definitely be reading more (this was a great book). The book reminded me a lot of Neal Stephenson's Anathem.
Wikipedia has a good plot summary. In brief, the book is in three parts, each 600 years apart. In the first (roughly 2600 a.d.) civilization has been destroyed by nuclear war and humans are living at primitive levels. Remnants of knowledge are kept alive in Catholic monasteries. In the second part (roughly 3200 a.d.) scientific knowledge is beginning to accelerate (here is a map of the relevant parts of the world at this time). In the final part (roughly 3800 a.d.) the cycle begins again and the book ends with another nuclear apocalypse.
The religious aspects of the story are obvious and very interesting. There is also a little on the divide between theoretical scientific work and actual experimentation (a theme brought more clearly in Anathem) which is also interesting and less often commented upon.
Here is the cycle of history:
I have to say, though I think the book is great, I don't think this is how history works. Worlds don't end with a bang, they end with a whimper. I'm not sure Mr Miller would necessarily disagree as he puts it:
Perhaps, for Mr Miller too, this (lack of) morality is the true, ultimate cause of the downfall portion of the cycle.