Within the sphere of the Know World is another world, the Hollow World. There your characters will meet ancient Nithians, long disappeared from the surface world and thought extinct: Blacklore Elves, living in a magical valley and served by automatons-devices that take care of everything, from serving their food to trimming their grass: Azcans, terrifying, war-mongering natives whose taste for battle extends even into their favorite game-the loosers always die- and many more. Monsters abound as well, from dinosaurs to aurochs.

In the Hollow World, the sun never sets. Magic works differently than it does "outside"-some spells don't work at all. And quite often, getting in is much, much easier than getting out.

A 128-page Dungeon Master's Sourcebook, with everything the DM needs to run an exciting campaign in the Hollow World. Also in this book are extensive entries on all the Immortals represented in the Hollow World: their interests, their allies, their enemies.

A 64-page Player's Book, including how-to's for creating a native Hollow World character and ways to bring a Known World character into the Hollow World. Included in this are new spells specifically for the Hollow World.

A 32-page Adventure Book, containing several starter adventures and entries on the various monsters found in the Hollow World.

Four full-size, full-color map sheets, showing the Know World and the Hollow World, and detailing the central, most populous areas of the Hollow World.

Ways and means to adapt this material to the Advanced Dungeons & Dragons 2nd Edition game!