It is everything that you can expect from Nancy Kress. It is a solid hard sci-fi, with some revelation made. I cannot help but to compare it with her previous novel that I read, Steal Across the Sky. I have the same feel when I read both novel. Both are related with alien encounter. Both also related with human genetics. Both also bring new revelation about our ancestor. I cannot help also to say that Steal Across the Sky has given me greater impact than this novel.
The novel is told using 2 POV, a researcher, stumbled on something that catch the attention of some aliens; and her son, an ignorant commoner. And the story is pretty much told from the circle of this family, and some closed friends. The story started with an alien encounter, with a hidden agenda. Once the agenda is not hidden, chaos followed.
First of all, this is a thin novel, only a little bit thicker than a novelette. I finished it in one sitting, without a sweat. I give a merit to Nancy because the flow of the novel is so great that it does not give me any speed bump while reading it. But unfortunately, being so thin, you cannot pack too may ideas inside it. Nancy has been doing well in packing all the necessary ideas inside this novel, plus the story, without making it too preachy with technical details.
Now, the down side. Nancy Kress has try to simplify the plot by ignoring all chaos that happened outside the labs. But even by cutting that parts away, she is still missing some interesting dynamics that might happened in her closed circle family and among her lab crews. It should be more interesting if she has more pages to write.
So, that is my final thought, it feels a bit incomplete. It feels that it ends too abruptly. And the final twist is a bit an anticlimactic. Sorry Nancy, only 3 out of 5 this time.
Additional Note (critical review with spoilers)
The hypothesis of Nancy Kress regarding the alien civilization is interesting. She hypothesized that due the more benign planet that the alien inhabited, they became a more cooperative society, compared to ours. And because they are more cooperative, they are far more advanced than we. That hypothesis needs to be explored at least another one hundred pages. Maybe in debates between alien and human, maybe in some scene when the alien are confused about our competitive, self-interested, individualized and obsessive behavior.