Snowman, possibly the last human alive, oversees a tribe of genetically engineered humanoids in a post-apocalyptic near future. The narrative moves back and forth in time between Snowman's attempts to survive in the present and his reminiscence about how the world got to be in such a mess and his own role in the catastrophe.
The Crake of the title was a brilliant scientist who was also Snowman's only friend. Snowman is basically Martin Freeman to Crake's Benedict Cumberbatch. Oryx was the woman who come between them, but her backstory is the most disturbing aspect of the book.
I am holding back a star because Atwood refuses to admit she is writing science fiction. If this novel were written by anyone other than an established literary figure any publisher in the world would have published it as science fiction. Still, it was the best science fiction novel of 2003 even if it is still in the closet about being SF.