Seriously, this is one of the best books I’ve ever read for my hobby. It’s basically a book full of stuff that happens around adventures/adventurers - the “mundane” stuff of the world. What’s the food like? How is time measured and observed? How does architecture differ by region? Are there sports?
Even if you’re not a Pathfinder player, it’s an awesome book for general world-building. Heck, I’d recommend it for people outside of the TTRPG hobby who are just into fleshing out their fictional worlds.