From the back of the book: "The Depths of Despair(TM) is the first in a series of D20 System(TM) setting books featuring isolated and dangerous environments--"Hostile Climes"--that may be dropped into any fantasy campaign! Inside is a detailed setting featuring a city at the bottom of a whirlpool and the caverns beneath, new skills, feats, gear, prestige classes, monsters, and a complete adventure to drop into your campaign right away!" Contributors note: Despite being labeled "first in a series," no additional Hostile Climes books were produced by Pinnacle.