Guards! Guards! by Terry Pratchett (1989)

I only recently dove into Pratchett’s Discworld oeuvre, and pretty much all of them have been hilarious and delightful. This is one of my two favorites 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.)