Briarwood Castle, No. 108: A Guidebook Based on the Invincible Overlord Series

"...Now you can be privy to the closely-guarded secrets of Briarwood Castle in this two-volume set, which includes The Briarwood Castle Guidebook and The Dungeon Book, plus a separate parchment GM's map depicting the dungeon controlled by Ralf, a lich whose quest for power could have a profound impact on the City-State..."