The Hollow Earth: At the Earth's Core and Pellucidar

Readers can now enjoy two action-packed, adventure-filled fantasies from Tarzan creator Edgar Rice Burroughs--At the Earth's Core and Pellucidar--in this one volume!
 
While working in the Sahara, David Innes--heir to a mining fortune--makes a shocking discovery: an unknown world exists below ground, at the Earth's core. Once trapped in this primeval land known as Pellucidar, Innes must battle an array of terrifying prehistoric creatures and primitive tribes if he is ever to return to the Earth's surface.

This new edition features a map of Burroughs' imaginary land plus a glossary of terminology.