You may recall the last time I addressed didacticism, in the context of children's books. Let's look at didactic stories for adults now, shall we?
I'm talking about this today because Ayn Rand is an excellent example of an author who wrote didactic stories. Warnings against certain aspects of society that, unchecked, would ruin us. Remember: by "excellent example of ... didactic" I mean "beats you over the head with a lesson until it's literally lodged in your brain meat."
Philip K. Dick is another author whose name pops up all over the place when you're searching for didactic adult books. Something about sci-fi written in the 1960s, it's incredibly didactic, full of explicit warnings about the future.
And you can't talk about dystopia and didactic without talking about George Orwell. Personally, I actually think he's one of the lesser offenders, unless you're talking about Animal Farm. Remember how that was my least favorite assigned reading in school? I knew I was being talked down to... for once, it wasn't because I was supposedly young and stupid, but I felt like anyone, teen or adult, reading that book would be talked down to.
When you get right down to it, most stories are didactic on some level, because most stories incorporate a lesson, whether on purpose or not. An example of behavior is shown to the reader, and consequences occur for the character who acted. Even if someone is shown doing something good and not being rewarded, or even being punished for it, you're learning that no good deed goes unpunished, or not to expect rewards for good behavior (perhaps you should be good for the simple reward of being good). But the books listed here make it obvious that they have a lesson to teach you, and you aren't going to get through the book without hearing it... a lot.
What didactic stories for adults have you read? How did you feel about them?