By my estimate, A Canticle for Leibowitz ranges in time from a century to roughly 15 centuries in the future, but when you realize it was originally published in 1959, it becomes clear just how informed by the Cold War and the post-nuclear nightmares of the mid-20th century this novel is. Centered on a community of monks that endures for generations as the keepers of ancient knowledge in the wake of a nuclear holocaust, one of its primary themes is the repetition of history; along those lines, it suggests that what we might perceive as the end of the world may indeed be anything but.
Divided into three sections separated by hundreds of years each, the novel opens after an unspecified man-made disaster (not stated as nuclear war, but certainly implied) has wiped out much of the Earths population, and most of whats left is scattered and damaged. Thanks to a Simplification intended to eradicate the educated and intellectual, those humans who remain have entered a second Dark Ages. And just as in the first one, the preservation of knowledge has fallen to the Church. The friars of the Leibowitz order have become protectors of the Memorabilia - documents that have somehow survived, although their meaning has been lost. Over the following centuries, the technological and scientific knowledge they contained will be slowly re-discovered...as if it is learned for the first time. And because, as the saying goes, those who forget history are doomed to repeat it, the last section of the novel finds the world on the brink of a horror similar to that which preceded the events of its opening third.
While plot summaries tell you what a book's about, they really don't say much about a book - and it's difficult to know WHAT to say about Canticle. I found it more accessible than I expected to, and it's certainly thought-provoking on numerous levels. The premise of a Church (implied, but not stated, to be the Roman Catholic one) that plays a major role in preserving and forwarding secular knowledge - ultimately becoming involved in space travel - reminds me of The Sparrow, although, to be more accurate, it's likely that Canticle was an influence on Mary Doria Russell's masterwork, since it was published earlier (in fact, Russell wrote a new introduction to the edition I read). Speaking of the Church, the fact that it's language is Latin here is another marker of when this novel was written - pre-Vatican II and the shift to liturgy in local languages.
Despite the commonalities with one of my all-time favorite works of fiction, including transcendence of genre and discussion potential, I doubt I'd have ever read A Canticle for Leibowitz if it weren't a Faith and Fiction Roundtable choice. Having read it once, however, I think theres a good chance I'll read it - and think about it - again.