Some might remember those homebrew articles, I posted some here before under a different account but I decided to remove them because I prefer it be linked to its own account to avoid crossing the IRL info/names ! If you do remember them please forget about it and don't mention the name of the other account :)
Anyway this is a homebrew book I wrote. The goal originally was to write a cool book item that was not magical, since all of the cool book items written for DnD/PF are magical and that's usually how it justifies their mechanics.
This is the journal of a strange serial killer who disappeared, and while not magical the reading will still have strong effects. Reading it for a while might reveal some secrets, formulas and crafting recipes hidden in the killer's notes, but also maybe clues about where they might have gone, or whether or not their paranoia had a kernel of truth to it...
I know there's most people still just play DnD 5e (try other systems, it's fun!), but this is probably still an idea you can steal/adapt into your own thing!