I wasn't aware that Ark was a sequel. This is the first Stephen Baxter book I've read. It's a quick read and I think if I hadn't been looking forward to a book about colonization of another planet, I may have liked it more. This book was much more about the possible social consequences of a really long space voyage. I also thought it was interesting that Stephen spent a lot of time with the people left behind. There were a lot of people who selflessly contributed to a voyage they would never benefit from except having the knowledge they may have contributed to the continuation of humanity.