No, I’m thinking about books where exploring or sorting out an idea (or answering a question) drives the story.
Mystery novels are the most common idea-based book. “Whodunnit? or “Whydunnit?” are questions that have to be answered, or the reader will throw the book against the wall, or at the author. Depending on the sub-genre, the characters may be flat or fleshed out, the setting could be very specific (Chinatown has to take place when and where it does, likewise Tony Hillerman’s mysteries) or “the big city of gritty streets and long shadows.” The crime could be considered an event, assuming there is a crime, but solving the mystery is what drives the story.
“What if” books also lend themselves to idea stories, especially short stories. What if a genetically modified plague kills all women (The White Plague by Frank Herbert)? What if a rogue asteroid or something rips Earth away from the Sun? What if house pets suddenly develop the ability to talk, and they are as tactful and restrained as you think they’d be? What if aliens arrive and offer humans everything we ever wanted (clean energy, bountiful and pest-resistant crops, cures to all ills) without any strings attached? Whatever it is, the entire story centers on studying and extrapolating from that idea.
I’d argue that The Handmaid’s Tale is at core an idea story. The characters are not especially memorable as people, or at least, none have stuck with me longer than the time it takes to read the book. The setting is not too detailed, landscape and environment don’t play a role, although culture does, and culture centers on the idea of an “Evangelical” totalitarian state taking over and in essence enslaving all fertile women. I vaguely recall a few events, but no single event drives the story. Everything in the book centers on exploring the idea Margaret Atwood developed.
Rendezvous with Rama by Arthur C. Clark could be considered an idea story, in my opinion. What if humans find an enormous space ship, and explore it? Some of the characters are interesting, and the idea of the Church of Jesus Christ, Astronaut still tickles me a little. But everything in the book focuses on the arrival of the starship and what people find inside.
Idea books are not my favorites, especially those written over the past decade or so. Part of my bias comes about because they seem to be more IDEA stories than about exploring ideas. I admit, I’ve tried writing idea stories and the results were so heavy-handed that even I winced, so I know how easy it is to turn a premise into a sledge-hammer. “Let’s explore a cool what if” seems to slide a little too often into “smother the story in an ideology with a topping of message.” Even when I agree with the idea, that gets old very quickly. Ideas that are poorly grounded also break the story for me. I personally need at least a vague foundation that makes logical sense.
A good idea story spins the story and idea in intriguing directions, but logical directions. Character, milieu, and events are still present, but you the author have to focus on the idea and working it, exploring the nooks and crannies, and satisfying the reader. “What if…?” “Whodunnit?” What if space aliens find Elon Musk’s car and begin to worship it? What if they find the car and decide that cars are enslaved and need to be liberated? What if TEOTWAWKI came along and we all felt fine?
Novellas and short stories are good for exploring ideas. However, this brand new novella explores Hamburg in 1892: