Although this is a stand alone story more than a sequel, Oryx and Crake and some other characters from that novel actually make an appearance in The Year of the Flood. Unfortunately I read Oryx and Crake about five years ago, so I can’t remember it too well, just that I liked it.
This book focuses on sometime in the not too distant future with The Gardeners (a sort of eco-focused religious group) and the post ‘waterless flood’ world. Atwood has a great imagination and her vision of the post apocalyptic, genetically modified future is fascinating.
I seem to be on a future themed trip lately (The Next 100 Years may actually not be a bad companion to this). I definitely recommend this, and if you haven’t read Oryx and Crake, read that too.