I read this book on my first day of jury duty. The premise is fairly interesting -- a Neanderthal scientist from an alternate Earth creates a portal to our Earth. In their Earth, Neanderthals became the dominant species. The interactions between humans and our primate cousins (siblings?) provide a neat opportunity to examine our assumptions about "human nature" and how things "have to be". Unfortunately, this promise is wasted with somewhat preachy contrasts between the pacifist, environmentalist Neanderthals and big, bad humans. (Or would that be small, bad humans?) There's even a bad guy from a shadowy government agency. Other negatives include a bunch of forced Star Trek references (the novel might as well have been stamped, "for nerds, by a nerd") and wooden writing.)

Of course, all of this was sealed by the complete botching of the explanation of mathematics used in the book. Worse, number theory (my field). Since that was laughable (I mean, couldn't the author run it by somebody who knew something and say, "Please make sure I don't embarrass myself?"), I questioned the plausibility of the various other disciplines tapped for this ambitious book.