A Canticle for Leibowitz is a compilation of three novellas which trace a post-nuclear holocaust Earth from shambles to the rediscovery of space flight. After the nuclear disaster, the "Simplification" causes the survivors to kill all academics, scientists, and otherwise smart people for their part in bringing about nuclear destruction, and books are widely burnt. Isaac Leibowitz, a scientist involved in the development of the Bomb founds a Catholic order of monks who smuggle books to a remote abbey in Utah and save them for the edification of future generations. That's just the backdrop--the actual story is of the different generations of priests and brothers who fight to preserve the collection of Leibowitz, who is eventually sanctified, even though they themselves do not understand what their collection means.
It's a cleverly simple idea, and this book is interesting simply because it's a deeply religious science fiction novel, of which there are few. It's an easy enough read--I read it in a mind-numbingly uneventful day--but it contains a lot of notable themes and ideas, such as the inevitable cycle of human history. It ultimately poses the question of whether or not the monks' attempts to civilize humanity are worthwhile, as the knowledge that they save ultimately threatens to destroy the earth a second time. The one thing I found a little irritating was the uncanny resemblance of the world that survived the nuclear holocaust to ours, the pre-holocaust world. Statement about the inevitable cycle, or lack of imagination? I'm not sure.