A SciFi trilogy created by Canadian author Creator/RobertJSawyer, about an AlternateUniverse where [[AllCavemenWereNeanderthals Neanderthals]] survived to modern-day and became the dominant species while normal humans (i.e. ''us'') went extinct in prehistory. The first novel begins when a FreakLabAccident accidentally teleports one of these advanced Neanderthals into our world. The rest of the series deconstructs and explores the differences and similarities in the parallel hominid societies.

The trilogy is comprised of ''Hominids'' (published 2002), ''Humans'' (2003), and ''Hybrids'' (2003).
!The Neanderthal Parallax includes examples of:
* AuthorTract: ''Hybrids'' spends a lot of time talking about how evil human males are, and how they've done nothing but bring evil into the world.
* BigBrotherIsWatching: With the Companion implants. Subverted, in that Neanderthals see this as a ''good'' thing, as it makes alibing yourself for crimes and identifying perpetrators easy. Except if suspected of a crime, no one monitors a person's recordings-they're only "unlocked" when a formal charge has been made.
* CanadaEh: The book takes place in Canada (specifically Ontario) on this Earth, as well as its geological analogue on the Neanderthals' Earth. Sawyer likes to set novels in his native country, especially in or around his home town Toronto, as most sci-fi has been US-based.
* CantArgueWithElves: The interactions between Neanderthal and human society start to look like this by about halfway through the first book, and continue throughout the series, with the Neanderthals taking the part of the "elves."
* EveryoneIsBi: Every Neanderthal has a male and a female mate. There may be aversions, but they aren't discussed in the books. Enforced by virtue of living in a segregated society (females all live in the city center, males all live on the rim; the two meet for four days out of every month that they periodically adjust to avoid or encourage fertility, with the latter occurring only once a decade to limit population growth). May also invoke SitchSexuality and/or IfItsYouItsOkay.
* [[FishOutOfTemporalWater Fish Out Of Quantum Water]]: Ponter on Human Earth, in spades. Mary later has similar troubles on Neanderthal Earth.
* ForeignQueasine: The Neanderthals don't have agriculture, and thus no alchohol, dairy products, bread, or spices. They seem to find cheese extra disgusting, because the idea of taking milk from another mammal and letting microorganisms spoil it is shocking. Inverted with Ponter's love for KFC.
** When Ponter is first offered Dairy, he, noticing that Homo Sapiens women have larger breasts then Neanderthal women, assumes it's ''their'/ milk. He's no less grossed out when he hears it's cow milk.
* HalfHumanHybrid: One of the major subplots is Mary and Ponter's struggle to have a child together.
* HumansAreBastards: And how!
* InterdimensionalTravelDevice: Decoherence caused by a quantum computer allows for travel between Human Earth and Neanderthal Earth.
* LadyLand: Any Neanderthal city's center will be entirely populated and run by women.
** NoPeriodsPeriod: Averted. Ponter is very surprised to note that one of the women from the Sudbury team is menstruating, but not all of them; coming from a society with an isolated female population, he's used to everyone being on a synchronized cycle. Back on Neanderthal Earth, Adikor is repeatedly accused of insanity for going downtown to talk to a female colleague during "Last Five," the last five days before the full moon. Apparently Neanderthal women get ''truly'' spectacular PMS, and all at once...
* LoveTriangle: Mary, Ponter, and Adikor. Partially subverted, in that Neanderthals all have two lovers, but that Adikor wants Mary to follow the Neanderthal rules, and Mary wants Ponter to follow human rules. [[spoiler: Eventually solved by Mary going [[EveryoneIsBi bi]] and taking a Neanderthal woman-mate.]]
* MarySueTopia: The Neanderthal society in the first book.
* MeaningfulName: In-universe. Due to Neanderthal jaw anatomy, Ponter can't pronounce the "ee" syllable. Therefore, he pronounces Mary's name as "Mare," which happens to mean "beloved" in the Barast language
* OutgrownSuchSillySuperstitions: The Neanderthals didn't have to outgrow them, because they never had them. Because of the different structure of their brains, they are biologically incapable of believing in an afterlife[[labelnote:Note]]Probably untrue, actually, since actual Neanderthal burial sites have ceremonial item placements suggesting that they were to be used in the next life[[/labelnote]], or a god.
** Deconstructed, as Ponter makes a sincere attempt to understand and respect Mary's beliefs, and the attitude of most of the Neanderthals in the series toward human religion is more puzzlement and curiosity than contempt. [[spoiler: The final book has all humans' brains change as well due to the magnetic pole reversal, which causes peace to break out in the Middle East, making it more of a straight example]].
** As a side note, the differing structure of the Neanderthal brain also means that they don't have UFO or other paranormal experiences and while they are technologically capable of space travel, they never developed the desire to do so as a result.
* RapeAsDrama: [[spoiler: Mary]]
* RapeIsASpecialKindOfEvil: When Ponter hears that [[spoiler:Cornelius Ruskin]] raped [[spoiler:Mary and Qaiser]], he goes over to [[spoiler:Ruskin's]] house and [[spoiler:[[GroinAttack castrates him]] so that he can't pass on his genes or repeat the act on another woman.]] This is the legal punishment for violent crimes in his society.
* SchizoTech: The Neanderthals never developed agriculture (or for that matter most of the technology related to it). They developed a theory of genetics by selectively breeding hunting dogs as opposed to crops. Also, they never developed space travel or the jet engine (although they do have powered flight in the form of hovercraft and helicopters). Likewise, fossil fuel technology is entirely unknown.
* ScienceMarchesOn:
** The research available at the time the books were written indicated that Neanderthals and ''Homo sapiens'' were genetically incompatible, which plays a pivotal role in the plot. New research shows the opposite: not only were the two species compatible, there was significant interbreeding.
** Dogs in the Neanderthal universe are physically indistinguishable from wolves. The reason given is that Neanderthals only selected for behavior and hunting companions, and did not care what their dogs looked like. Research with tame silver foxes has shown how selecting for tameness inevitably results in other neotenous traits (short legs, larger skulls, folded ears, curled tails), even without specifically breeding for them. With this in mind, Neanderthals would have had to actually put a great deal of work into breeding dogs that still resembled wolves in any way shape or form, and the primitive appearance of dogs would actually have had to be very deliberate.
* ShownTheirWork: Robert J. Sawyer knows quite a bit about physics, chemistry, and biology and shows it off frequently throughout the books.
* StrawmanPolitical
* SuperiorSpecies: The Neanderthals tend to fall into this. One of the main points in their favor is that '''they themselves''' have a hard time accepting the idea that they may be significantly better than their ''Homo sapiens'' cousins.
** They are also capable of acknowledging their own faults (which are displayed by several characters across the trilogy).
* WellIntentionedExtremist: The Neanderthals are quite militant in the view that they can breed social harmony into their species by eliminating violent individuals from their gene pool - a policy enforced by [[{{Squick}} surgically sterilizing]] not only the offender, but also anyone sharing more than half of his/her genome. Of course, [[WriterOnBoard in-universe this seems to be true]]. Not to mention that they also sterilized everyone of low intelligence, raising their collective IQ a standard deviation, which is another goal of eugenics.
** UtopiaJustifiesTheMeans: Deconstructed; the reason behind the policy has to do with the fact that Neanderthals are, on the whole, ''very'' physically strong (hint: they routinely hunt mammoth using only wooden spears), and a simple dispute could easily end up with someone getting killed (one major plot point in the first book involves one Neanderthal character being struck by another. The loser got his jaw essentially destroyed with one punch, and even that was a pulled punch; if the other party had taken a full swing and he hadn't pulled away it would have been fatal.) It's stated that in the past, Neanderthal political assassinations were done by just walking up to the target and smashing their skull in. This is also probably why they never had many wars-it's stated in the books that the last one took place decades back, and even then only 78 people were killed (which is apparently ''high'', from the way they reflect on it).
** Also subverted, in that [[spoiler: we see in ''Hybrids'' a weak link in the Neanderthal justice system: a case of domestic abuse which would normally be punishable by castration. Unfortunately the woman refuses to press charges because she does not want to be responsible for sterilizing her children too, and only escapes by going to live on Human Earth, which obviously would not work for all Neanderthal abuse victims. It's a ''major '' flaw if the couple has children.]]