Pellucidar

The land of PELLUCIDAR, a place where dinosaurs roam through the jungles, and where saber-toothed tigers hunt the mastodon and mammoth. A tiny sun, the molten core of the Earth, hangs in the center of the heavens, shedding perpetual daylight upon Pellucidar. The land curves "upwards", as if you were standing on the inside of a gigantic bowl. Humans dwell in Pellucidar as well, stone-age men and women who must fight to survive in this savage world. Even worse, these people have been made slaves of the Mahars, a race of intelligent but sinister reptiles who look upon humans as nothing more than beast of burden or as tasty snacks in one of their ghoulish ceremonies. David Innes discovers this new frontier for mankind. He strives to carve a civilization out of its Stone Age perils. But the kidnapping of the beautiful cave-women-empress, Dian, makes him drop his fight for advancement enter into a still greater battle against all the primitive monsters of Pellucidar!