Edgar Rice Burroughs (1875-1950) was an American novelist most famous for creating the character of Tarzan, yet he also wrote science fiction adventures. As well as stories set on Mars, or Barsoom as its inhabitants know it, and five set on Venus, many more are set in lost worlds that time forgot on Earth. One series of novels is set inside the Earth, which is found to be hollow, in the fantastic land of Pellucidar.

Creation

Burroughs decided to become a full-time writer in 1911 and began writing the first in the Pellucidar series in January 1913. His idea, originally titled The Inner World, was set inside the Earth; at the time many scientists believed it was possible for the Earth to be hollow. This idea had first been seriously proposed by Edmond Halley of Halley's Comet fame in 1692, but Marshall B Gardner's A Journey to the Earth's Interior or Have the Poles Really Been Discovered (1913) was a key influence.

Of course there had been numerous myths, legends and novels about underground worlds written prior to Burroughs', of which the most notable are Journey to the Centre of the Earth by Jules Verne (1864) and A Strange Manuscript Found in a Copper Cylinder (1888), originally anonymously published but accepted to be by James de Mille, and noted for being the first Canadian science fiction novel.

Pellucidar

The Pellucidar novels are set on the inner surface of Earth's hollow sphere. In the story, the Earth's crust is only 500 miles thick. When the Earth was formed it was a hot, rotating, nebulous mass that cooled and shrank. Centrifugal force hurled out the heaviest elements to form an outer, solid layer that became the Earth's crust – our surface. While the Earth continued to shrink it made a vast hollow interior filled with a breathable atmosphere and at the very centre a small super-heated core that acts as the inner world's sun. Surrounded on all sides by the solid crust, gravity keeps this sun in the very centre of the Earth and it lights every surface of the inner Earth eternally.

Humans and a vast array of other species are perfectly capable of living on the interior of the Earth's surface because gravity pulls them towards the centre of the crust, rather than the centre of the Earth. The only ways to get to Pellucidar are either by tunnelling through the crust or by travelling through an entryway at the North Pole.

By some unexplained process, the oceans of Pellucidar are directly under the continents of outer Earth and vice versa, so Pellucidar has the same ratio of land to sea as the outer Earth does sea to land. This means that in terms of land mass, Pellucidar is much larger than outer Earth, with 124,110,000 square miles of land compared to 53,000,000 square miles. Despite this vast area, the main characters frequently bump into each other unexpectedly. If the heroes encounter someone they don't know on their travels then the person is almost certainly either the chief or king of a village or the partner or offspring of a chief or king. Saving them from almost-certain death is the best way to ensure you are welcome in their village, otherwise all tribes on Pellucidar are suspicious of strangers and will put them to death. Every woman met is inevitably a young, single princess about to be married against her will who will inevitably fall in love with a rescuing stranger.

There is an inner moon, which orbits a mile above Pellucidar's surface. This takes 24 hours to orbit the central core sun, which means that, as the Earth rotates at the same rate, it always appears above the same part of Pellucidar, named the Land of Awful Shadow. Here the land is bathed in a perpetual eerie twilight, such as that experienced during an eclipse. It is believed that spirits of the dead travel there, so it is named the Dead World.

Pellucidar is inhabited by prehistoric creatures, such as sabretooth tigers¹, called 'tarag' in Pellucidar, pterodactyls or 'thipdar', mammoth or 'tandor', dinotherium (prehistoric elephant, the Pellucidarian name for which is unknown), phororhacos² or 'dyal', flying stegosaurus or 'dyrodor', triceratops or 'gyor', hyaenodon or 'jalok', brontosaurus or 'lidi' and of course the Tyrannosaurus rex, called a 'zarith'.

'Pellucidar' is named after the word pellucid. Like 'Lucid' this word usually means 'transparent' and 'clear and understandable', but originates from the Latin per- meaning 'very' and lucidus meaning 'bright'. The land is therefore called 'very bright' to emphasise the fact that the land has an eternal sun and no night.

Gilaks

In the inner world humans are called 'Gilaks'. Outwardly identical to us, they have developed a homing instinct like a pigeon which allows them to navigate in a world without stars or a rising and setting sun, although this only works on dry land. The instant that they are on water they completely lose all sense of direction. They often have names consisting of a name and a description, such as Dian the Beautiful One or Ghak the Hairy One. The character with the most unusual name is undoubtedly 'Old Man whose name is not Dolly Dorcas'.

Gilaks are extremely tribal. When they encounter someone not from their village they either kill or enslave them if they are male, or enslave/marry them if they are female. The idea of co-operation in the face of the various prehistoric dangers that surround them never seems to occur to them.

The Science of Pellucidar

Burroughs's work was considered 'science fiction' in its day. One feature distinguishing science fiction from fantasy is that anything unusual is explained using science rather than magic. In his Barsoom (Mars) books, for example, Burroughs imagined the thin, natural atmosphere of the planet being augmented by an atmosphere factory - by adding electricity to a type of electromagnetic radiation unknown on Earth, air was produced. Of course, the author's grasp of science is often rather tenuous - such an explanation makes as little sense as invoking magic would.

It can be interesting and amusing to consider the 'scientific' facts and explanations which Burroughs presents as a background to an adventure story, but that is a subject for a separate Entry.

The Novels

In common with many of his other stories, Burroughs presents the Pellucidar novels as true events experienced by others. Many of the early novels have elaborate prologues detailing how Burroughs came to learn the tales in order to publish them. These too are included in the summaries below.

1. At the Earth's Core (1914)

This 37,000-word story was written between January and February 1913. It was first published as a serial in All-Story Weekly in four weekly chapters in April 1914 and was published as a novel in 1922. It has also been serialised under the title Lost Inside the Earth.

David Innes has inherited a mining corporation and when his friend Abner Perry invents an 'iron mole' mining machine, they try it out. When it malfunctions, they find themselves travelling 500 miles to the centre of the Earth and emerging in a strange land ruled by Mahars, eight feet tall telepathic pterodactyls who enslave humans and feast on human flesh. Lacking any perception of sound, the Mahars communicate with their servants and slaves by sign language and with each other by 'project[ing] their thoughts into the fourth dimension, when they become appreciable to the sixth sense of their listener.' This ability also allows them to hypnotically control the minds of humans to stop them resisting when they are being eaten. Having webbed feet, Mahars are also at home in water and are as aquatic as penguins. As only females are born they reproduce artificially using what is called 'the Great Secret'.

Captured by the Mahars' gorilla-like servants called the Sagoths, Perry and Innes befriend fellow captives Ghak the Hairy One, ruler of Sari, and his niece, Dian the Beautiful One. Dian had fled her home of Amoz as she was being forced to marry Jubal the Ugly One against her wishes. They also encounter Hooja the Sly One. Hooja and Dian disappear while the others are taken to the Mahar capital, Phutra, where they learn the Mahars' great secret. Innes manages to escape and saves the life of Ja, ruler of the island of Anoroc³.

Dare Innes return to Phutra to rescue Ghak and Perry? Will he discover what happened to Dian and persuade her to marry him? Will he return to the surface world? Can Hooja the Sly One be trusted? What impact will the introduction of bows and arrows have on an unsuspecting inner world? Who will be crowned Emperor of all Pellucidar?

The prologue explains that Burroughs learned these events after travelling to Africa to hunt lions, where he encountered Innes and a captive Mahar. This is the story as Innes told it.

At the Earth's Core was adapted into Amicus Productions' penultimate film in 1976. Amicus Productions was a British film company in the 1960s and 1970s and Hammer's closest rival. Best known for horror films, particularly portmanteau stories, it also made comedies and science fiction, including two 'Dr Who and the Daleks' adaptations starring Peter Cushing.

2. Pellucidar (1915)

Written between November 1914 and January 1915, Pellucidar is a longer story (61,000 words). It was first published as a five-part serial in All-Story Weekly in May 1915, for which Burroughs was paid $1,522, and it was first published as a novel in 1923. It neatly ties up the loose ends of At The Earth's Core.

Innes briefly visited the Earth's surface to gather supplies, including guns, and has returned to Pellucidar, but emerges in an unknown land. Reunited with Perry, he learns that the imperial alliance has been shattered by Hooja the Sly One who has set all the tribes he had united against each other, leading to humans once again being easy prey for the Mahars.

What has happened to Dian? Can they survive a journey across the inner world's sea? Who are the gorilla-sheep people? Will Innes be eaten by a fierce hyaenodon? How will the introduction of gunpowder make Pellucidar a safer place?

Burroughs learned this story after David Nestor, who was in Africa hunting a rare antelope, discovered a telegraph box in the Sahara Desert that had been placed there by Innes on his journey back to Pellucidar. The story was dictated along the wire by Innes in Morse Code.

3. Tanar of Pellucidar (1929)

Written between September and November 1928, 14 years after the previous book. First published as a serial in monthly magazine Blue Book between March and August 1929, for which Burroughs was paid $7,500, this 78,000-word story was published as a novel in 1930.

Tanar the Fleet One is Dian the Beautiful's cousin. He had been sent to investigate reports that a harquebus-armed enemy had assembled an armada to invade the Empire. Captured by the Korsars, a piratical people who have primitive gunpowder weapons and aim to conquer Pellucidar, Tanar is brought on board their flagship and meets Stellara, beautiful daughter of their leader the Cid. Meanwhile, an unsuccessful rescue mission is led by Innes who, unbeknown to Tanar, is also captured.

During a violent storm Tanar and Stellara are stranded on board the damaged vessel when everyone else launches lifeboats. They land on the island of Amiocap. Although it is famed as the island of love, they are soon condemned to death.

What is Stellara's secret? After the usual round of being captured, separated, reunited and constantly haunted by jealous misunderstandings, will Tanar and Stellara realise their feelings for each other? Can they survive capture by the cannibalistic Buried People and pretty much everyone else they encounter? When Tanar and Innes end up imprisoned in separate underground oubliettes, cut off from daylight and each other with only the snakes in the cell for company, who will escape?

Burroughs came to learn the story after his neighbour, inventor Jason Gridley, was developing a new form of radio. The Gridley Wave allows radio communication between Earth and Mars and picked up transmissions being broadcast by Perry in Pellucidar.

4. Tarzan at the Earth's Core (1930)

Tarzan at the Earth's Core follows on immediately from Tanar of Pellucidar. Jason Gridley, having learned that Innes, who he has never met, is still imprisoned in the cells of the Cid, decides to mount a rescue mission. He knows the best man for the job is Tarzan of the Apes, and before you can say 'me Tarzan, you Jason'⁴, he agrees.

Tarzan's inventor friend Erich von Harben⁵ constructs an airship, the O-220⁶, out of a light metal he discovered. The airship is commanded by Tarzan with Jason Gridley second in command and Lieutenant Frederich Wilhelm Eric von Mendeldorf und von Horst, or 'Von' for short, as airship's mate, with ten of Tarzan's Waziri warrior friends as part of the crew. The airship also carries a lightweight scout aircraft. After travelling to Pellucidar through the polar opening, Tarzan leaves the airship to explore, but is captured by Sagoths. Jason, Von and the Waziri search for him, but they are caught in a vast stampede of animals caused by a pack of hundreds of hunting sabretooth tigers. They are all separated, with Jason the only one to return to the airship. After trying to search for the others using the scout plane, the airship is destroyed by a pteranodon who attacked it thinking it was food, and he lands in time to prevent the beautiful Jana, the Red Flower of Zoram, from being captured by four men from a different tribe who want to make her their mate.

Will Jason and Jana reveal their true feelings for each other or will she snub him until the very end of the story? Can a stegosaurus really glide through the air using its plates as wings and its tail as a rudder? Who will be captured by the lizard-people? Is the painfully stereotypical portrayal of Robert Jones the airship's black cook forgivable? When Tarzan meets the Red Flower of Zoram, will he say: 'Me Tarzan, you Jana'?

5. Back to the Stone Age (1937)

Written between January and September 1936 under the title Back to the Stone Age: A Romance of the Inner World⁷, this story was published six years after Tarzan at the Earth's Core. First published in six weekly issues of Argosy in January and February 1937, Burroughs was paid $1,000 for the 80,000-word story. In September the same year Burroughs' own publishing company, Edgar Rice Burroughs, Inc printed it as a novel.

This novel begins at the same time as Tarzan at the Earth's Core and follows the adventures of Wilhelm von Horst on the surface of Pellucidar after he is separated from the rest of the airship crew during the mission to rescue Innes. Can he survive being poisoned by pteranodons, captured by cannibals and stalked by sabretooth tigers?

6. Land of Terror (1944)

Land of Terror was written between October 1938 and April 1939. The 60,000-word story was rejected by all the leading magazines of the time and was not published until May 1944, by Edgar Rice Burroughs, Inc, and is unique in being the only Pellucidar story not to have appeared in a magazine. It is generally acknowledged in being the weakest in the series.

After travelling far from his empire in an effort to find von Horst, Innes is captured by the bearded warrior women of Oog, who come from a land where men are the weaker sex⁸. After befriending another slave, Zor, they escape only to be captured by the Jukans, a race who are probably the most civilised people on Pellucidar despite all being quite as mad as hatters⁹. Innes also learns that the Jukans have captured Dian the Beautiful. She had been leading a rescue expedition to find him but had been attacked by Do-gad, nephew of the king of Suvi, who wished her to be his mate. Zor and Innes escape with a slave girl, Kleeto, but Dian has disappeared. After befriending a mastodon family, Innes, Zor and Kleeto are captured by man-eating giants.

Will Innes defeat the Goliath-like Azarians? Will they survive the encounter with giant ants? What are the Floating Islands and why do they move? Will Innes be reunited with Dian?

7. Savage Pellucidar (1942 & 1963)

Savage Pellucidar consists of four novelettes¹⁰. The first three were written in late 1940 and published in magazines in 1942 ¹¹. The fourth novelette in the collection was written in 1944 and did not appear in print until 1963, following a resurgence in Burroughs' popularity after his death.

1. The Return to Pellucidar

Burroughs wrote the first story under the title Hodon and O-aa¹², after the two main characters, but it was published in Amazing Stories in February 1942 as The Return to Pellucidar, even though none of the characters had left Pellucidar to return there.

On the outskirts of Innes' confederated empire lie the tribe-states of Kali and Suvi. Suvi leaves the empire and declares war on Kali. Hodon is dispatched to investigate and meets O-aa, the daughter of the King of Kali, but is unable to warn Innes of the Suvians' betrayal before Innes is captured. They escape but are captured by the sabretooth men, meeting the Old Man whose name is not Dolly Dorcas, a man from the outer world who cannot remember his own name, only that of his ship whaling vessel, the Dolly Dorcas. He fell into Pellucidar through the polar opening many years earlier. Meanwhile Perry invents a gas balloon¹³, but when Dian the Beautiful tests it, the mooring rope is unsecured leaving her to drift out of control.

2. Men of the Bronze Age

First published in Amazing Stories in March 1942, this story continues immediately after The Return to Pellucidar. The balloon carrying Dian lands in a previously unknown continent or large island across the sea, home to Bronze Age city-states. The people of Lolo-Lolo worship Dian as the goddess Noada. Meanwhile O-aa had been kidnapped by an island-dweller but she kills him in self-defence shortly before the ship she is on is hit by a severe storm. She is also washed up near where Dian's balloon landed but in the rival city-state of Tanga-Tanga, where she too is worshipped as Noada.

3. Tiger Girl

First published in Amazing Stories in April 1942. After returning to Sari, Innes learns that Dian had been carried away by a balloon, so has Perry build another balloon in the hope it will head in the same direction and lead him to Dian. Meanwhile Hodon heads out to sea hoping to find O-aa while the Old Man whose name is not Dolly Dorcas builds Pellucidar's first clipper ship, the John Tyler, and leads a rescue mission to find them all. Who will find whom only to then be separated by events beyond their control? Who will be surrounded by sabretooth tigers?

4. Savage Pellucidar

The search and rescue missions battle storms, betrayal and dinosaurs while everywhere O-aa and Dian go they encounter tribesmen who wish to take them as their mate. Will everyone finally be reunited and live happily ever after?

When Burroughs died in 1950 it was assumed that everything he had written had been published. In the early 1960s his novels were released in paperback, leading to a resurgence in his popularity. Following the retirement of manager Cyril Rothmund, the Edgar Rice Burroughs, Inc office was reorganised and catalogued and several previously unpublished works were discovered, including Savage Pellucidar. The original ending of 'Tiger Girl' in which everyone was reunited and lived happily ever after had been changed to keep the main characters separate until the very end of this short story.

Review

The Pellucidar novels are highly enjoyable escapism that should not be taken too seriously. They are a product of their time and attitudes have since moved on. For example the novels were written with the Edwardian Boys' Own adventure perspective: though the natives of Pellucidar are noble and brave, David Innes and Abner Perry patronisingly are able to revolutionise and improve their lives. The novels are definitely pro-imperial and in true The Man Who Would Be King style, Innes founds an empire and becomes Emperor.

Similarly, in Pellucidar women are often treated as objects. Marriage is a solemn undertaking that a man can enter into through:

• Kidnapping, such as when Dacor the Strong One stole Canda the Graceful One from her people.
• Placing the largest carcass outside the woman's father's house.
• Defending a woman from another man and then holding her hand. Immediately raising her hand and dropping it indicates she is released, but failure to hold or raise her hand enslaves her.

Although all women are damsels in distress who are prone to being kidnapped and need saving from many different types of savage animal, they are not completely helpless. Most are fierce and proud and more than capable of stabbing potential kidnappers, while the heroes too are always finding themselves imprisoned and imperilled by both men and monsters. Women never reveal their feelings to those they are attracted to, preferring their potential partners to feel the agony of rejection until the very last page, no matter how many times they are rescued from certain doom. Especially if there is a misunderstanding that keeps them apart.

There is no denying that the general assumptions and attitudes of the time in which they were written have influenced the stories. Written in an era in which big game hunters were considered heroes rather than ecological vandals, all animals encountered in Pellucidar are considered fair game to kill without regret. Like most books from the period, there are sentences scattered throughout the series that would be unacceptably racist or sexist if written today. In 1963 the Pellucidar novels were slightly edited. For example the sentence 'As the three men seated themselves, Robert Jones entered from the galley, his black face wreathed in smiles' became 'As the three men seated themselves, Robert Jones entered from the galley, his shining face wreathed in smiles'. Quite why is unclear as Robert Jones still talks in stereotypical pidgin English. Perhaps the most disturbing sentence in the series is:

Perry was trying to perfect poison gas. He claimed that it would do even more to bring civilisation to the Old Stone Age.
- Land of Terror, Chapter I

Did You Know...?

• Jason Gridley, Tarzan, David Innes, Abner Perry and von Horst are all mentioned in the first two pages of Burroughs' first Venus novel, Pirates of Venus (1932). Jason Gridley's radio system, the Gridley Wave, is also used to communicate with Mars in A Fighting Man of Mars (1930).

• Pellucidar also appears in various Tarzan comic strips, cartoons and live-action episodes.

• Various fan fiction works have been written over the decades, including published sequels, the best known of which is Mahars of Pellucidar by John Eric Holmes (1976). Similarly, Lin Carter was inspired by Edgar Rice Burroughs to write the Zanthodon novels.

• Pellucidar really exists! The deepest cave system in the United States is the Lechuguilla Cave in Carlsbad, New Mexico. One of the chambers has been named Pellucidar, with the balcony above named Barsoom.