Edgar Rice Burroughs launched the Pellucidar cycle of seven novels with At the Earth’s Core. Penned in January 1913, it was his sixth story written for magazine publication, following his sequels Gods of Mars and The Return of Tarzan. In the novel, Connecticut mining heir David Innes invests in eccentric inventor Abner Perry’s “iron mole,” a mechanical drilling vehicle with which they hope to prospect subterranean ore. The device malfunctions, marooning the two of them in a mysterious land inside the hollow earth, populated by cavemen, dinosaurs, and other prehistoric fauna. It was Burroughs’s first Stone Age story.
The notion of the earth as a hollow sphere dates back at least to a 1692 paper by Edmond Halley, discoverer of the famed comet that bears his name, who postulated a series of concentric spheres with polar openings. In 1818, John Cleve Symmes expanded this theory, even petitioning the U.S. Congress for funds to launch an expedition to locate the polar opening.
Lands inside the earth are a recurrent theme in genre fiction; Jules Verne’s Journey to the Center of the Earth (1864), with prehistoric beasts and giant primitive men, is perhaps the best known of the genre.
In Pellucidar, there is no night and no time – due to a tiny central sun, it is permanently high noon. The horizon curves upward into the haze of the distance. Land and water areas are transposed from the outer earth, resulting in a greater land mass than the surface world. There is a small pendant moon, which rotates with the earth, thus remaining permanently over the mysterious Land of the Awful Shadow. The Pellucidarian moon is another of Burroughs’s undeveloped ideas, tossed into the series, perhaps in view of a sequel that remained unwritten.
The first two novels of the series, At the Earth’s Core and its sequel Pellucidar, concern the protagonists’ efforts to lead a revolt against the Mahars, a malevolent race of rhamphorhynchus-like reptiles that have enslaved the humans, whom they consider a delicacy. The Mahars, an all-female race, communicate by exchanging thoughts in the “fourth dimension” and have no hearing or spoken language. They are the most intellectual race in Pellucidar, scientists who perform vivisection on humans, whom they consider dumb animals. Mahars are aided by their minions, the Sagoths, hairy missing-link apemen, who enslave the races of cavemen of the Earth’s core.
In Tanar of Pellucidar, Jason Gridley discovers a previously undiscovered radio frequency, and soon stumbles across Abner Perry’s broadcasts from Pellucidar. Ever the incompetent inventor, Perry invents a radio in Pellucidar, but can only broadcast in a frequency not receivable by the outer world – until Tarzana tinkerer Gridley discovers the frequency and names it the Gridley Wave.
This third inner-earth tale introduces Tanar, a cave warrior who journeys across the land and faces the Korsars, seagoing brigands descended from buccaneers who sailed into the inner world through a polar opening. Innes’s imprisonment by these Korsars spurs Jason Gridley and Tarzan’s rescue mission in Tarzan At the Earth’s Core.
Lieutenant Wilhelm von Horst, a mate on the O-220, is separated from the mission and left behind in Pellucidar. Back to the Stone Age, a sequel to Tarzan at the Earth’s Core, details his struggle for survival among the savage tribes and animals, including the Ganaks, minotaur-like creatures and Gorbuses, a hellish cannibalistic race of albinos.
Land of Terror, the sixth tale, is another book of Odyssean wanderings, as David Innes and a rescue party locate von Horst, and seek their way home. David and his mate Dian face more strange creatures and cultures, including the warrior women of Oog, the mad Jukans, and man-eating giants of Azar.
In Savage Pellucidar David and Dian encounter the men of the Bronze Age cities Lolo-Lolo and Tanga-Tanga, as their ally Hodon the Fleet One pursues his love O-aa across the inner world. The tale is further enlivened by the comic relief of Ah-gilak, “the little old man whose name was not Dolly Dorcas,” a nineteenth-century sailor stranded in Pellucidar.
One authorized sequel to the Pellucidar series has been published. Mahars of Pellucidar (1976) by John Eric Holmes relates the tale of Christopher West (named for Holmes’s son), a scientist whose heroics and mighty weapon win him the sobriquet Red Axe. At the Earth’s Core was filmed by Amicus productions in 1976, and the Pellucidar tales have been adapted to the comics by John Colman Burroughs in Hi-Spot Comics #2, 1940, and later in DC’s Weird Worlds and Tarzan Family in the 1970s.