Ponter Boddit is a theoretical physicist working with his professional and life partner--his man-mate--Adikor on a quantum computer, deep in the bowels of a nickel mine, when something goes horribly wrong and, from Adikor's perspective, Ponter disappears.
From Ponter's perspective, he's suddenly in a tankful of water in a large, dark room.
Ponter and Adikor are Neanderthals, from a world where H. sapiens sapiens died out, and H. sapiens neanderthalis survived to become the dominant species.
Now Ponter is stuck in our world, where he emerged into the heavy water tank of a neutrino detector deep in a nickel mine in northern Ontario. Reuben Montego, a medical doctor, and Mary Vaughn, a very distinguished geneticist who has done work on recovered Neanderthal DNA, are two of his major allies in this world, but he's facing a huge challenge, building a new life for himself, isolated from everything he's ever known. And since Neanderthal society is much lower-density, the total Neanderthal population much lower, and they never developed agriculture but instead have systemitized hunter-gatherer food collection and distribution, modern industrial civilization with a population in the billions, is very tough for him to quickly absorb.
Meanwhile, back home in the Neanderthal world, the woman-mate of Ponter's late woman-mate has accused Adikor of murdering Ponter. She's not deterred by the lack of a body; Adikor was the only person there when he disappeared, Adikor has a volatile temper, and Adikor, to her way of thinking, must have been jealous of Ponter's greater prominence in their shared profession.
Also, Adikor can't explain quantum physics in a way that makes sense to an adjudicator who was apparently never required to study any science.
There's a lot to like about this book. The science is interesting, though not as new and startling as it was in 2002, and the Neanderthal society is really, really interesting. And who can dislike a world where woolly mammoths still roam North America?
But I do have some problems with it, too.
I won't deal with Mary Vaughn's rape and its aftermath, as others have done that at some length.
It's more than a mite annoying that the contrast between our society and Ponter's is largely used as an opportunity for one-sided criticism of ours. H. sapiens hunted most of the megafauna to extinction. (This is no longer believed to be true.) H. sapiens wiped out H. neanderthalis. (This is no longer believed to be true, and with another decade of research, we now know there was interbreeding among Sapiens, Neanderthals, and Denisovans.) We still have violent crime. We do not successfully feed all of our very large population. We pollute the air. And, oh dear, we have religion.
What's interesting is that Ponter assumes without question that H. sapiens wiped out H. neanderthalis in our world, and H. sapiens wiped out H. sapiens in his world. It would seem that there's another possibility, especially since the means by which the Neanderthals have effectively culled violent behavior from their genome could not possibly have begun until they had advanced scientifically enough to reason out the genetics.
What's annoying is the discussion of religion between Ponter and Mary. Mary's a Catholic as well as a world-class geneticist, and might reasonably be expected to have a slightly more sophisticated understanding of religion. It's treated as an unquestionable fact that religious believers believe that religion, belief in God, is a necessary precursor of morality. That's a belief that is troublesome in many ways as well as demonstrably false. But having been raised Catholic myself, albeit in a different country than Mary was, I was taught that, on the contrary, the moral impulse comes first. "If anyone says "I love God," and hates his brother, he is a liar, because he who does not love his brother whom he has seen, cannot love God whom he has not seen." 1 John 4:20 (English Standard Version) In short, that the innate moral impulse is a necessary, but not a sufficient, condition for belief in God.
Robert J. Sawyer is a smart guy, and knows how to do research. Perhaps he didn't realize he needed to do research on this. Certainly, if he had incorporated this view of the relationship between religion and morality, as taught by the religion Mary is said to believe in, it would have made Mary's position in that discussion rather stronger--perhaps uncomfortably so, for the agenda Mr. Sawyer seems to have been pursuing.
Now, it's not that he portrays the Neanderthals as perfect. By no means. It's just that Neanderthal failings seem to be matters of individual character, while Sapiens failings are shown as systemic and pervasive, despite the fine characters of Ponter's friends in this universe.
I think the ideological blinders do weaken the story and the book overall, but I like Ponter, Adikor, and their friends on both sides of the portal, and overall I enjoyed the book.
Recommended with reservations.