Small Gods by Terry Pratchett (1992)

My other favorite Discworld book so far.

(For anyone new to these who might be interested: I'd say they're like if Douglas Adams wrote fantasy comedy instead of science fiction comedy, but there are several dozen of them, comprising a variety of connected sub-series (broken down visually here). There are a lot of suggestions out there for what order to read them in, but mine would be: Start with Small Gods (a stand-alone book that takes place probably a couple thousand years before the others) and Guards! Guards! (the first of the City Watch sub-series). If you're hooked, then just go back and read the rest in publication order. If you find that you're mostly liking only some of the sub-series or want to read them that way, then you can use the visual guide to go through just those in order.)