I read this as part of my "reading all the Hugo winners" goal.
All I have to say is: This book was up against China Mieville's 'The Scar' - and THIS won? WHAT?
Sorry, but this is just not a very good book.
The premise is that, due to an accident that occurs during a quantum physics experiment, a Neanderthal scientist from a parallel universe where humanity is the race that went extinct, finds himself stranded in our world.
There's plenty to work with there, lots of potential. However, that potential is not realized.
The book is written in the style I like to refer to as "late 20th-century Mainstream Bestseller." However, this breezy beach-read style is broken up by extended awkward and unbelievable dialogues. Sawyer's point is to show the problems of our society by contrasting it with his imaginary Neanderthal society. Unfortunately, his way of doing this is to get two characters stuck in a room together and make them talk at length, in a very stilted, artificial manner about the topic at hand.
So we get to hear polemics on religion, gender relations, overpopulation, etc, etc. I absolutely agree with some of Sawyer's opinions, I disagree strongly with others. Whether or not I agree with his points is not relevant, the problem is that the topics are introduced and discussed in such a clunky fashion.
Also, as a woman, I felt that Sawyer showed a significant lack of understanding of women in general. His depiction of the reactions of a female character who is raped read like they come straight out of some psychology text, without ever genuinely getting inside her head or creating empathy. I also objected to his depiction of a gender-separatist society that apparently has developed because women are so bitchy due to PMS that men have to live separately from them. I will admit the actual existence of PMS (supposedly it occurs in 2 to 5% of women), and maybe Neanderthals could potentially be more susceptible to it. But yeah, Sawyer's depiction of women in general rubbed me the wrong way.