Dawn, by Octavia Butler
When I looked through the library SF collection for older books to read in January, I came across this too, and I remembered that somebody in the book blogger universe had reviewed it very positively a little while ago, so I grabbed it too. Dawn is the first book in the "Xenogenesis" series, and I'm really interested to see how it goes; this was a fascinating read.
Lilith is one of the few survivors of an all-Earth war that rendered the planet uninhabitable. She wakes up alone, in the cell of a spaceship. Aliens have taken her and some few hundred other survivors and kept them in hibernation for long years, until Earth is again ready for habitation. Their species survives by trading DNA with other species every so often, and they plan to help humans re-establish life on earth -- but human children will no longer be quite human. Lilith is expected to learn survival skills and become the leader of a group, but she's also expected to persuade everyone to go along with this plan. She has no intention of doing so, but there don't seem to be any choices she can live with.
This is a great setup and a really good story that asks some really interesting questions. I enjoyed it a lot, and I'll be reading more.