At this year's Pure Speculation convention, I attended a panel in which paticipants argued the relative merits of Dune, A Canticle for Liebowitz, and Spin. We were asked to vote for one of the books at the end. At first, the question posed was which book was most worth reading, but few people were prepared to make a judgement. It was then suggested that we vote for which book we most wanted to read after listening to the discussion. I had recently re-read Dune, which put it out of the running, and I decided to vote for Canticle. The idea of post-apocalyptic monks definitely had me intrigued.
I have read Canticle now, and I was not disappointed, though I don't think I would quite put it ahead of Dune on the list of must-read SF books. It happens that I read it right after reading The Chrysalids, which was an interesting contrast. The question of whether, if our civilization destroys itself, we can continue to see human life as worthwhile is at the heart of both books. Chrysalids takes a secular view in which Darwinian competition for survival is the ultimate morality, while Canticle presents the world from the point of view of fervently and uncompromisingly religious monks.
The villains of Chrysalids are bigoted fundamentalists, while those of Canticle are worldly men, bent on gratifying their own pride. It is quite easy to see in the telepathic utopia of Chrysalids exactly the sort of impatience with our own imperfections with which Canticle accuses secular culture. Likewise, the monks of the Order of Liebowitz can be compared to the religious community in Chrysalids: like them, they seek to preserve the past rather than improve on it, and submit unquestioningly to authority and tradition.
Both books ultimately declare humanity, at least in its current form, incapable of overcoming its destructive tendencies. However, they then proceed to opposite conclusions about the value of human life. In Chrysalids, the genocide of all humanity save the evolved few is seen as an act of mercy. Canticle takes the other extreme, arguing against euthanasia even in the case of someone who has nothing to look forward to but a painful death.
My own views fall somewhere between the two extremes, but if I was asked to vote between these two books, Canticle would win hands down. I found the characters and ideas in it human and engaging, though also challenging, whereas those in Chrysalids left me feeling sickened. I'm sure other readers will differ, though. If you have read this far, please post your opinions on the matter, and perhaps cast your own vote as to which of the two is the more worth reading. I think this could make an interesting discussion.