I don't know what id want in that book; or rather - I wouldn't want to read it (at first).
Before you get your chainmail pantaloons all up in a twist, I'd rather have an adventure path that explores it and takes the players in a journal. And I'd like "my" GM to run us through it while I (playing a character who met my current character) chronicle the journey. Then, the adventure path, the setting book, and the chronicle all are published together.
Paizo, give me a call, eh? I'm sure we can make this happen.