A sourcebook for those players of D&D who really like to understand why their demons are so chaotic and evil, I suppose real fans of all things abyssal will really find this book worthwhile, but I must admit, it didn’t do much for me. Basically, the book is thus: after a run through D&D demonic lore, rounding out some new demons, and a discussion of the demon lords (which often feels a bit repetitious to those who have the ‘Book of Vile Darkness’), and some good descriptions of various layers of the Abyss, there’s nothing new. There are feats, but they’re repeated feats from other works. There are spells, most of which your PC wouldn’t use, but will be nice for the DM to toss at the players. But is there enough fresh and interesting information here to make the price worthwhile? Not for me. Unless you’re going for a demon-centric campaign, I’d skip this sourcebook.