Raft (1993) by Stephen Baxter, tells the story of a few thousand humans in an increasing hostile environment, located in an alternate, high-gravity universe. They are divided in classes, they fight against each other, and they have eventually to leave in order to survive. Nominated for the Arthur C. Clarke Award in 1992, it’s also the first story in Baxter’s amazing Xeelee Sequence. The Sequence, composed by many stand-alone books, features a far-away future and an alien race called Xeelee, in one of the most coherent, hard SF universes ever conceived.
