A Canticle For Leibowitz, by Walter Miller Jr.
In the future, after a nuclear apocalypse, monks try to preserve unintelligible past science for future generations (including an order of monks devoted to the saintly Isaac Leibowitz, a presumably-Jewish seemingly-low-level electrical engineer from the before-times).
I read this entirely because of After Virtue, which introduces itself by describing Canticle and saying how we live in a similar after-time for morality, where we barely understand the words being used and don't get any of the concepts but pledge allegiance to this cargo-culty version of what ethics used to be. This is a BANGING premise and I immediately bought Canticle, which I finished before finishing After Virtue because fiction is much easier than non-fiction, a general problem in my life. I also feel like I should learn to be more careful/deliberate about what I read, because "a guy used this novel as a metaphor in the beginning of his philosophy book" is not a good way to assign one of the limited slots remaining to me for Books I Will Read In My Life.
Because it bothered me not to know: a canticle is "a hymn, psalm or other Christian song of praise with lyrics usually taken from biblical or holy texts." Not really related to the book to be honest.
The book was generally fun! It had some good ideas and ways of expressing the underlying conceit, of making you see what cargo-culting and imitation without understanding look like in a society not your own (because, of course, we're doing the same things but it's hard for us to notice it). E.g. the monks laboriously copy out old technical blueprints by filling the page with black ink and leaving only white lines, instead of drawing black lines on white paper, because that's how the blueprints that reached them look.
(I wasn't actually sure what that was about, whether it was something to do with nuclear fallout or mimeographs or old xeroxes or.... but in the fine tradition of writing these bookthoughts forcing me to actually look stuff up, here is why old blueprints were white on black:
The cyanotype process started with a drawing on semi-transparent paper that was weighted down on top of a sheet of paper. The drawing was then placed over another piece of paper, which was coated with a mix of ammonium iron citrate and potassium ferrocyanide (from an aqueous solution and then dried). When the two papers were exposed to light, the two chemicals reacted to form an insoluble blue compound called blue ferric ferrocyanide (also known as Prussian Blue), except where the blueprinting paper was covered and the light was blocked by the lines of the original drawing. After the paper was washed and dried to keep those lines from exposing, the result was a negative image of white (or whatever color the blueprint paper originally was) against a dark blue background.
Another well-observed aspect of this regressed future is that the Great Scientists are doing a different kind of work than the scientists of a "new frontiers" world: in one of the core passages of the book, the Abbot of the monastery observes bitterness from the the Galileo/Newton-ish super-scientist figure, and realises it's because the scientist, despite his extraordinary brilliance, knows he is only re-doing work that others had done before, will never make any truly original discoveries, and in some sense is not even doing "real science" -- science is inductive, and here the task is deductive, trying to re-discover e.g. how to generate electricity out of the fragments of often-overly abstract knowledge that has been randomly preserved in papers and diagrams from the before-time, and "reasoning which touches human-level experience nowhere".
Having grown up in a time that assumed (assumes?) everything keeps getting better, I think it's fascinating and possibly-important to think about the possibility of the world getting substantially worse, whether in dramatic ways like in Canticle or in a more humdrum stagnation-or-decline kinda way. I don't know what to do about it psychologically, because at present my most successful friends seem to be people who have been irrationally (to me) optimistic about the world and been rewarded for it, and my pessimism has never actually helped me even when things did turn out bad. But maybe I just didn't invest/commit to my pessimism properly!
Unrelated: I realised, too late, that this book is actually a fix-up of three previously-published short stories, each set 600 years apart. I really wish they'd made that clear in the audiobook -- I don't think they even announced the move between Parts explicitly, so I was just super confused how one thing led to another, and why the plot was so disjointed. I thought the third story was also just very different thematically, I don't think this book holds together super well as a single object. (It does highlight the excellence of the old improv comedy trick "referencing something that happened much earlier, even glancingly and not super relevantly, makes the brain think there is continuity throughout the piece and satisfying completed-ness" -- the author clearly went back and threw in little glancing references to the previous stories in the later stories, and it really does make the work feel more cohesive even though those references are really pointless and unimportant e.g. a character finds a statue in the basement that we realise was one mentioned in the 600-years-ago last part, but this has no importance and is just glanced at for a single sentence!)
In its 1000-year-spanningness and themes of cyclicality and change, this book reminded me of the remarkable Last And First Men by Olaf Stapledon (and in other ways the not-yet-bookthoughted Three Body trilogy....)