The Neanderthal Parallax is a trilogy of novels by Robert J. Sawyer. It depicts the effects of the opening of a connection between two alternate Earths: the world familiar to the reader, and another where Neanderthals became the dominant, sentient hominid. The societal, spiritual and technological differences between the two worlds form the focus of the story.
The trilogy's volumes are titled Hominids (published 2002), Humans (2003), and Hybrids (2003). Hominids first appeared as a serial in Analog Science Fiction, and won the 2003 Hugo Award for Best Novel; Humans was a 2004 Hugo Award finalist.
The initial contact between the two worlds takes place at the Sudbury Neutrino Observatory, which is also the location of a scientific research facility in the Neanderthal world.

Terminology
Barasts are dedicated hunter-gatherers, and have no developed concept of agriculture. Despite this, they are still technologically advanced, possessing quantum computers, helicopters, and communication and recording biological instruments. They live in a strong ecological harmony with their environment, using clean energy, living homes, and keeping a constant population. They measure long periods of time in lunar months, not years. Also, the total barast population is much lower, numbering only 185 million worldwide compared to the gliksins' 6 billion.

Family life
The barast world has a single government hierarchy: each region of the globe is governed by a local Grey Council; these in turn answer to the High Grey Council, the world government.
About eight decades before the time of the novels, companion implants were perfected and issued to all barasts. These are comprehensive recording and transmission devices, mounted in the forearm of each person. Their entire life is constantly monitored and sent to their alibi archive, a repository of recordings that are only accessible by their owner, or by the proper authorities when investigating an infraction, and in the latter case only in circumstances relevant to the investigation.
Any serious crime has a single punishment: the sterilization of the offender and all others who share at least half his genes (parents, siblings and children). This eugenic practice serves to keep any undesirable elements out of the gene pool without severely punishing an offender, beyond his loss of a genetic heritage.
As a result, serious crime of any sort is virtually unknown in the barast world.

Government and justice
In the barast world, lower population levels and the absence of large-scale agriculture mean that many species exist which are extinct on the gliksin version of Earth. These include not only birds such as the passenger pigeon, but also megafauna such as the woolly mammoth. Also, forests are much more extensive in the barast world because there was no need to cut down forests on a large scale. Barasts have domesticated wolves as companions, but have not bred them into the many varieties of the domestic dog. A gliksin may become fearful upon seeing a barast dog, thinking it a wild wolf. A barast, seeing a gliksin's dog such as a dachshund, may wonder if the creature really is a dog.
The climate in the barast world is also somewhat cooler, because of the lack of greenhouse gases compared to the gliksins' Earth. Barasts are not as heat-tolerant as gliksins, probably because they evolved on a cooler Earth and also due to their greater muscle mass. As a result, tropical regions of their Earth are just as underpopulated as the polar regions on the gliksins' Earth. A significant story feature is the state of the Earth's magnetic field. In the barast world a reversal of polarity happened shortly before the story starts and caused no noticeable harm to the barasts. As to why the pole reversals are off by several years, it is ascribed to random small differences over the intervening 40,000 years. In the gliksin world it is happening as the stories take place; this has an effect on the minds of gliksins, who have brain structures the barasts do not possess (see Religion).

Religion
by Lois McMaster Bujold