Pellucidar

Edgar Rice Burroughs' Pellucidar is the second in his series about the fictional "hollow earth" land of Pellucidar.

In the incredible world inside the Earth, David Innes discovers a new frontier for mankind. He strove to carve a civilization out of its Stone Age perils. But the kidnapping of the beautiful cave-women-empress, Dian, made him drop his fight for advancement enter into a still greater battle against all the primitive monsters of Pellucidar!

Emerging in Pellucidar at an unknown location, David frees his captive. He names the place Greenwich and uses the technology he has brought to begin the systematic exploration and mapping of the unknown land while searching for his lost companions, Abner, Ghak, and Dian the Beautiful. He soon encounters and befriends a new ally, Ja the Mezop of the island country of Anoroc.

Edgar Rice Burroughs was an American author, best known for his creation of the jungle hero Tarzan, "Lost worlds" and the heroic Mars adventurer John Carter.