David Innes is a young man who has just inherited a large mining company. An eccentric inventor, Abner Perry, convinces Innes to underwrite a project to build an 'iron mole', claiming it will make them both wealthy. The mechanical beast works well, actually too well. On the maiden voyage, instead of digging for a few minutes and returning, they plunge straight through the earth's crust into the 'inner world' of Pellucidar. This world resembles earth but is a horizon-less, primeval tropical landscape where the sun neither sets nor rises, and is populated by 'Sagoth' gorilla men, wild human slaves, and the ruling hypnotic reptilian 'Mahars'. Upon arrival at this strange world, the men are immediately captured and enslaved. But soon Perry learns to read the language of the Mahars, and discovers a secret way to turn the tables! True to Burroughs form, this non-stop fantasy thriller weaves together savage islanders, pterodactyls, telepathy, and, of course, romance.
I was born in Connecticut about thirty years ago. My name is David Innes. My father was a wealthy mine owner. When I was nineteen he died. All his property was to be mine when I had attained my majority—provided that I had devoted the two years intervening in close application to the great business I was to inherit. I did my best to fulfil the last wishes of my parent—not because of the inheritance, but because I loved and honored my father. For six months I toiled in the mines and in the counting–rooms, for I wished to know every minute detail of the business. Then Perry interested me in his invention. He was an old fellow who had devoted the better part of a long life to the perfection of a mechanical subterranean prospector. As relaxation he studied paleontology. I looked over his plans, listened to his arguments, inspected his working model—and then, convinced, I advanced the funds necessary to construct a full–sized, practical prospector.