Clay's Ark

I didn't see how this fit into the Patternmaster series much at all until I finished the fourth book, but damn did Octavia Butler know how to write aliens. The invading species hybrid with humanity is eerie and very clearly foreign, yet it assimilates so completely with humans that even the reader ends up on its side some of the time. Some of it. Which is exactly how the kidnapped family feels, I imagine. Making the two daughters bi-racial is a brilliant move too, emphasizing the two worlds the characters already inhabit. This book asks us to look a humanity and what its survival really means.