Ark is a 2009 hard science fiction novel by English author Stephen Baxter. It is a sequel to his 2008 novel Flood. Ark deals with the journey of the starship Ark One, and the continuing human struggle for survival on Earth after the catastrophic events of Flood. The series continues in three pendant stories, which are described in the plot summary below. Being hard SF, Ark contains many references to unrealised or hypothesised technology (Project Orion, the Alcubierre drive), physics (antimatter), and hypotheses about extraterrestrial life. Baxter credits several books and academic works in an afterword: See Scientific background below. Source: Wikipedia (en)