The setting for a series of science fiction novels by Creator/JackChalker, beginning with ''Midnight at the Well of Souls'' in 1977. The Well World is a planet-sized computer created by an ancient race that used it to expand and stabilize the universe; its surface is a series of 1560 hexagonal laboratories used to develop new sentient species with carbon-based lifeforms in the southern hemisphere and truly alien lifeforms in the north. Newly arrived space travellers are incorporated into the experiment by being automatically assigned to a "hex" and transformed into its dominant species. Control the Well World and you can theoretically control the entire universe. Of course, it's never that simple.

Main series:
* ''Midnight at the Well of Souls'' (1977)
* ''Exiles at the Well of Souls'' (1978)
* ''Quest for the Well of Souls'' (1978)
* ''The Return of Nathan Brazil'' (1980)
* ''Twilight at the Well of Souls'' (1980)
* ''The Sea is Full of Stars'' (1999)
* ''Ghost of the Well of Souls'' (2000)

Watchers at the Well side series:
* ''Echoes of the Well of Souls'' (1993)
* ''Shadow of the Well of Souls'' (1994)
* ''Gods of the Well of Souls'' (1994)
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!!The ''Well World'' series employs the following tropes:
* ActionSurvivor: Nathan Brazil. Despite being the immortal guardian of the universe, he's small, unimposing, and doesn't normally go looking for trouble. His survival is guaranteed but his integrity is not and he's been mutilated quite a bit over the years, and while the stuff he loses always grows back it's a long and painful process.
** He only seems small in the modern era. He's only slightly less than average sized for a paleolithic human, and most of human history was spent in the paleolithic era.
* AllMythsAreTrue: Centaurs, fairies, fawns are real alien races. Earth was created in seven (subjective) days. Nathan Brazil was Judas Iscariot, as well as the inspiration for the WanderingJew.
* AmnesiacGod: Nathan Brazil in the first novel, before the Well restores his memories.
* AndIMustScream: The final fate of Juan Campos, the South American rapist drug lord from the Watchers at the Well trilogy. [[spoiler: Nathan Brazil decides a fitting fate for Campos is to be dropped into the body of a gorgeous, mute South American Indian woman, who has wandered a bit too close to the Campos compound around the time that the Family's henchmen are looking for some fun. To add squick to the matter, Brazil's Modus Operandi is to find people who have recently died, and bring them back to life with the soul of the person he's dealing with. Campos, my boy, you are now a zombie sex slave for the family you were once groomed to lead. And only you will ever know or believe it. Sleep well.]]
** The fate of a bad guy in the first book. [[spoiler: He's dropped into the body of a deer-like animal on the home planet of a species of humanoid which hunts said animal in packs and eats it alive. Wanting to avoid such a grisly fate, he hurls himself off a cliff ... only to wake up in the body of ''another'' deer. Brazil made sure he will experience death repeatedly, once for every person whose death he is responsible for. He has a fair body count to his credit. And the worst part: ''he doesn't know'' that it will, eventually, end.]]
** The fate of Damon Hain, a drug dealer and slave trader. The Well transformed him into a into female breeder of a giant spiderlike species. Her new people brainwashed her into a loyal and adoring subject of the local warlord prince. When the group reaches the Well, Hain's only wish is [[spoiler:to mate with her beloved Prince. Brazil grants her wish, transforming Hain into the most beautiful female ever seen and sends her home. When the rest of the group demands to know why the villain gets rewarded, Brazil explains that the nobody told Hain that her new race's infants hatch from eggs inside their mother ... and ''eat their way out''. Cue horrified and squicked expressions on every face...]]
* AlternativeContinuity: ''The Sea is Full of Stars'' -- a series about a group of travelers to the Well World that doesn't include Marva Chang or Nathan Brazil, forcing the heroes to solve their dilemma without a walking DeusExMachina.
* ArcWords: the phrase "Until midnight at the Well of Souls" is found in all Well World languages. We learn why in the first book (that's when the Well is open for entry) but it isn't until the fifth book that we learn there is a much deeper but no less literal meaning lurking underneath.
* ArmlessBiped: The inhabitants of Slongorn, although one could theoretically count their probosces as arms.
* AssimilationPlot: The State, in an AlternateHistory where the Soviet Union never fell, and Communism became the default human government, tries to make this a reality on many of its more "advanced" planets, engineering humans in birth factories to be physically flawless but mentally ant-like workers and on some worlds even hermaphrodites, so everyone's equal.
* AuthorAppeal: Even a casual survey of Chalker's work will show that he was obsessed with the idea of humans changing their species and sex. The ''Well World'' books just gave him a justification for doing it on a massive scale.
** Not to mention the recurring cases of strong-smart-woman-turned-virtually-helpless-by-vision-or-reading-impairment-and-body-morphing. Seems to happen in the majority of Chalker's books.
* BeePeople: Many hyper-communist human colony-worlds have begun evolving in this direction, although they haven't gone so far as to develop a single queen who does all the breeding (yet).
* BiTheWay: Brazil. It's couched in the terms of "if you live long enough you'll try anything" but it's a rather understated and matter-of-fact for a book written in 1977 when alternate sexualities tended to be either ignored or waved at the audience for shock value.
* BizarreAlienBiology: several hundred hexes worth.
* BizarreSexualDimorphism
* BlessedWithSuck:
** Nathan Brazil, is effectively immortal and something like God, but most of the time he does not consciously realize it. He remarks that no matter what the disaster, he has been a survivor, no matter how awful the event was.
** Brazil also has a tendency to bless other characters with suck, usually as a karmic retribution for something they've done.
* CharlesAtlasSuperpower: Gypsy ([[spoiler:Dr. Zinder]]) has learned to directly manipulate minor local aspects of the universal programming, without technological assistance -- he claims it's all done mentally using mathematics.
* CompleteImmortality: Nathan Brazil, [[IHaveManyNames among other names he uses]]; later, [[spoiler:Mavra Chang]].
* ConMan: both Brazil and Mavra Chang use this as their fallback survival strategy. Brazil's life is just one big con anyway.
* CosmicRetcon: Happens a few times, using the powers granted by the Well.
* DismantledMacGuffin: In the last Well World series, the villains are attempting to find all the pieces of the dismantled Straight Gate. As it was an artifact of the Markovians, it was indestructible, so it had to be split up, scattered, and removed from the history books to keep it from being misused.
* TheDreaded: Brazil, despite being an inoffensive sort, has the power to theoretically end the universe, and that terrifies everyone.
* EmergencyTransformation: In ''Midnight'', Nathan Brazil's soul is transferred into a deer-like creature when his human body gets fatally wounded. (Later, after he gets access to his powers, he obtains a new body for himself, but at the time it's expected to be irreversible.)
* EnforcedTechnologyLevels: Each hex has a maximum technology level -- Non, Semi, or High -- to simulate the availability of resources in that race's target biosphere. Technology above a hex's maximum level will simply fail to work inside that hex. Hex tech levels are not enforced on their species in the wider universe, however.
* ExpansionPackPast: Nathan Brazil, which is sort of inevitable considering he has (he says) rebooted the universe, and subsequently relived the whole course of all human history, at least five times.
* TheFairFolk: An insectoid race that can abuse physical laws by their outstanding psychic powers, essentially making them magical for all intents and purposes. Brazil theorizes that the Well is cheating for them to make up for something they ares supposed to have in their native environment.
* FateWorseThanDeath: Nikki Zinder [[spoiler: is one of the founders of the Olympians, the race that Ben Yulin created through Obie's powers. When the other founders figure out they're all reaching their age limits, they go back to the Well World for one last life time. Nikki, on the other hand, uses cybernetics to stay alive and becomes a brain in the jar to continue leading her people. When you first see her in ''The Return of Nathan Brazil'', she seems relatively sane until Mavra leaves the room. Then she goes on a religious rant and orders her people to make sure Brazil doesn't fall into the "Evil One's" hands, before laughing madly and then begging in a child's voice for her father to come back to her, despite the fact that she can't reasonably think he's still alive.]]
** [[spoiler:He is. He has to MercyKill her or her insanity will get in the way of saving the universe.]]
* FisherKingdom: Entering the Well World induces transformation into one of that world's indigenous races.
* FlyingDutchman: Nathan Brazil is an immortal wanderer, and is said in-story to be the likely inspiration for both the Flying Dutchman and wandering Jew legends.
* FormulaicMagic: The Great Equation. A couple of supercomputers are capable of warping reality retroactively (that is, those who didn't see the change actually happen are incapable of realizing that anything changed) by "altering" the Equation, which basically is reality. By moving a few numbers in the equation, the result -- that is, our reality -- changes to suit.
* FreakOut: In the second book of the second series, a fairly subdued version happens to [[spoiler:Alowi, as she insists on being called from then on out]] when [[spoiler:she's afraid that her husband is dying and realizes that she loves him]]. [[GenderBender The fact that she'd been male (and very straight) until not long before the wedding]] played into that as well.
* TheFogOfAges: In the first book, Nathan Brazil is so old that he's forgotten most of his life, including his own origins; it all comes flooding back when he comes (back) to the Well World.
* GenderBender: Numerous.
* GenderRarityValue: The Olympians are a subspecies of TranshumanAliens specifically created to exploit Gender Rarity Value to fulfill a male villain's harem fantasies -- fantasies that backfired spectacularly.
* GodInHumanForm: Nathan Brazil.
* TheGreatPoliticsMessUp: Later revised as the [[CosmicRetcon universe is rebooted]]. In earlier ''Well World'' stories, communism spread to the stars and there were even people who worshipped Marx and Lenin. After the universe was rebooted, the stories which (partially) took place on modern Earth noted that things are different.
* HandyFeet: The Twosh are bowling pin shaped creatures with only two limbs, which they use as hands or feet as the situation requires.
* {{Hermaphrodite}}: Several species, mostly aquatic, as well as variant humans.
* HumansAreWhite: Averted with Nathan Brazil, who is described as having a dark complexion, black hair, brown eyes, and a Roman (aquiline) nose. He's Semitic and he looks it, because he has to look like someone who wouldn't be too out of place in the Mesopotamian "cradle of civilization".
** Secondary protagonist Marva Chang looks Asian due to plastic surgery intended to hide her from those who would harm her birth family. When she is transformed on the Well World into a form which she believes to be based on her true form had she been allowed to grow up normally it's blond and busty, which would have made her extremely exotic looking (and thus difficult to hide) by prevailing human standards.
*** Brazil notes early in the first book that most people either look generic or engineered and names rarely match appearances.
* HurricaneOfPuns: Those hex names which aren't {{shout out}}s or nonsense words. Like "Wasdamaddah".
* HumanityEnsues: Inverted when various human characters are given alien forms and come to take on attributes of those forms.
* ImmortalInfertility: Nathan Brazil, which he actually considers a mercy since if he hadn't been he'd have outlived a ''lot'' of mortal descendents by now.
* LadyLand: The Olympians, a matriarchal society of transhumans that evolved, ironically enough, out of a failed attempt to create a society based entirely on ''male'' harem fantasies. (The ten-female-to-one-male birth ratio proved to be a bad idea in retrospect.)
* LaserGuidedKarma: If you make it to the Well of Souls with Nathan Brazil, better hope you were a good person.
* LastOfHisKind: Nathan Brazil, although he keeps changing his story about what his kind is exactly.
* LivingRelic: Nathan Brazil.
* LizardFolk: Marquoz starts life as one of a small saurian fire-breathing race. After reaching the Well World, he is reborn as a Hakazit, a race of huge armored dinosaurlike war machines.
* MagicVersusScience: In some hexes the differing laws of physics allow "magic" of various sorts, which [[DoingInTheWizard is in fact]] all just the MagicalComputer doing its thing.
* MasterComputer: For the ''entire universe''.
* MermaidProblem: The mermaid-like Umiau are hermaphroditic, not shy about that fact, and not at all interested in sex outside their species.
* TheMindIsAPlaythingOfTheBody
* MisterSeahorse: Literally (via MixAndMatchCritters).
* MixAndMatchCritters: Justified as lazy Markovians cribbing each other's work.
* MultipleChoicePast: Brazil has at varous time claimed to be {{God}}, the last member of a race of {{Precursors}}, or an ordinary human who was tricked into becoming the caretaker of the universe. [[spoiler:It's actually the second one.]]
* NeuroVault: In ''Midnight at the Well of Souls'', Vardia Diplo 1261 is, for the most part, a human cassette reel -- a NeuroVault with legs. A message is encoded in her head, to be shuttled to another planet's embassy, where the vault is unlocked, and she's basically written over with the base "Diplo program".
* NonMammalMammaries: A naga-like species with six arms and six breasts, though these were later retconned into glands for storing water.
* NoSexAllowed: Taken to extremes by the Comworlders, most of whom are genetically or biochemically engineered to never hit puberty.
* NowWhat: every group that makes it into the Well confronts this to one degree or another.
* OneGenderRace: The Czillians, a species of sentient, parthenogenic plants
* OurCentaursAreDifferent:
** The original series has Dillians and Rhone (which are basically the same race on two different planets) as more-or-less the classic model (albeit with horse ears, and only about the size of big ponies). Dillians also appear in the Watchers at the Well series; there, they're stated to have become a smoother synthesis of hominid and equine than the classic centaur.
** The matriarchal Gekir felitaurs.
* OurDragonsAreDifferent
* OurMermaidsAreDifferent: The Umiau are an alien species of aquatic mammals that just happen to look remarkably like traditional mermaids. Another aquatic race resembles sea lions.
* PatchworkMap: The surface of the Well World is divided into regular hexagons, each featuring its own environment, often startlingly different from its neighbors in climate, biome, atmosphere, gravity, or even achievable tech level, with no apparent separating mechanism other than force walls that just about anyone can shove through without noticing. A case of it being artificially constructed and designed that way.
* PatchworkWorld: The Well World is a planet constructed by the Precursors as a testbed for the species they designed and spread through the universe. It's divided into thousands of sections that mimic the conditions of each target planet.
* PhlebotinumKilledTheDinosaurs: The Markovians killed the dinosaurs because they'd evolved naturally on a planet that was earmarked for the Markovian-designed human race.
* PlantAliens: The Czillians are bipedal sentient plants. They are a lot more plant-like and a lot less humanoid then many of the other examples.
* PluckyGirl: Mavra Chang absolutely refuses to give up despite all of the BodyHorror inflicted on her -- seemingly cripplng mutations and body modifications only seem to make her even more determined. Hell, Mavra's probably ar her most dangerous when she doesn't even have any hands.
* PowerPerversionPotential: Obie's a supercomputer hooked up to a Matter/Energy/Matter converter and planted inside a planetoid big enough to house a small town. He can give you anything you want, as long as he knows how to make it, and has a big transmitter capable of altering entire planets to a person's specifications. He's also capable of traveling to anywhere he knows the coordinates of within minutes. Upon hearing of Obie's full power, Nathan Brazil himself said, "to hell with porn," and upon seeing Obie in action, Brazil was rather disturbed.
** One of the first acts of Ben Yulin, the villain in Book 3 upon gaining control of Obie is to capture two of the woman characters and transform them into what he considers female perfection as well as program them to be his sex slaves. He keeps doing to this to all the other characters he captures increasing the size of his harem, with plans of doing the same to entire worlds.
* RagnarokProofing: The Well World itself. Not only is it a planet sized computer that has been functioning for millions of years since its creators disappeared. [[spoiler:But if true Ragnarok is at hand you can just ctrl-alt-del the thing and reboot the entire universe.]]
* RealityWarper: Anyone who gains access to even some of the power of the Well World computer (or develops an analogous system). The human-built computer Obie has the power to warp a planet. The Well is the operating system for the Universe, and has been rebooted several times (thankfully by the good guys).
* {{Retcon}}: Brazil's origin story changes a lot over the years, explained in story as a combination of ShroudedInMyth and Brazil being a habitual liar.
* [[SenseFreak Sense Freak]]/[[ShowingOffTheNewBody Showing Off The New Body]] as each character awakens to discover their new species.
* RockBeatsLaser: Even in semitech hex sophisticated weapons are often useless, so people who travel a lot tend to carry things like swords and crossbows, which work anywhere.
** Some of the non-tech species are as sly and sophisticated as anyone, despite their enforced primitivism.
* SecondLawOfGenderBending: also applies to all of the ''species'' bending, as well.
** It's [[JustifiedTrope justified]]; the Well alters the mind of anyone passing through it just enough to make them comfortable in their new forms.
* SeriesContinuityError: The details of exactly what's in each hex of the Well World, and what each hex is named, are not always consistent from book to book.
* StarfishAliens: Well World is divided into two parts. Southern Hemisphere is for carbon-based lifeforms, and a lot of those are quite starfish-looking. Northern Hemisphere is for non-carbon-based ones, and those are just plain weird.
* TheStarsAreGoingOut: An experimental weapon tears a hole in reality that just keeps widening, erasing everything inside it.
* SteamPunk: In certain hexes, technology is limited to steam.
* SufficientlyAdvancedAliens: The Markovians.
* ThereAreTwoKindsOfPeopleInTheWorld: Serge Ortega asserts that the universe contains only three kinds of people -- scoundrels, hypocrites, and sheep -- and that he is therefore proud to be a scoundrel.
* TimeAbyss: Nathan Brazil, who is several times older than the universe.
* TransformationRay: One of the main manifestations of the Well's reality warping powers.
* {{Tuckerization}}: Many hex names are {{shout out}}s to people Chalker knew in SF fandom and the publishing industry.
* WanderingJew: Brazil again, and he's been wandering for at least a ''billion'' years.
* WaveMotionGun: The entire universe is actually a simulation running on a gigantic computer called the Well of Souls. Humanity figures out how to hack it to a minor degree and builds "Zinder Nullifiers" for use in a major intergalactic war, weapons that basically reformat a large region of space into a default empty vacuum state. The war gets a bit heated, the Nullifiers are overused, and the Well World starts suffering a progressive memory fault that will eventually destroy the entire universe unless our intrepid heroes are able to get into the Well of Souls' control center to fix it.
* WhatIfGodWasOneOfUs: Maybe, but also practically yes. Nathan Brazil's real origin is never stated, and several of the characters wonder about him: is he really God, the last Markovian, or a construct of the Well itself? At the end of the day, it doesn't matter because once he's in the Well Computer, he is a deity. [[spoiler: The last book reveals he is indeed the last Markovian.]]
** This is essentially the plot of the first novel, where the adventuring party reaches their goal only to discover that one of their own members is effectively god after they get there.
* WhatMeasureIsANonhuman
* WhenTheClockStrikesTwelve: The significance of the phrase "midnight at the Well of Souls" -- the six gateways to the Well open at local midnight. [[spoiler:That was the time the shift changed and it was the only automatic access left in the system.]]
* WhoWantsToLiveForever: Brazil, in his darker moments. [[spoiler: But what do you expect from someone who's been forced to destroy and recreate the universe at least ''five times''?]]
* WritersCannotDoMath: Look at the partial maps of the Well World and the data given in the text. Try to extrapolate the possible numbers of hexes. 1560 is ''not'' a possible result.

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