The kind of fantasy novel where you can't really make sense of it unless you keep a wikipedia tab with the French Revolutionary Calendar open on it while you read
@mcc There are a several novels I have where I have to keep a reference of some kind at hand when reading them.
The Name of the Rose -> Latin dictionary
Any number of books (but particularly those set in Imperial Rome) -> OpenStreetMap
The Count of Monte Cristo -> the hand-written sheet of A4 I made 20 years ago and keep folded int he book, with a diagram of all the characters' relationships on it.
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