Kim Stanley Robinson is an American science fiction writer, who has written around 20 books since the 1980s; this is the first I've read. It's epic and ambitious, a little under 500 pages. It opens 160 years into an multi-generation colonisation expedition to a star system 12 light years from Earth, having left our solar system in 2545. The star ship has a population of around 2000, supported by self-contained biomes. The infrastructure and biology of the ship is beginning to decay as the ship approaches the system they are to colonise, and when the colony fails, the decision of whether to return to Earth has to be made.
The book is concerned with the science of interstellar travel, artificial intelligence, and the human aspects of conflict and decision making in a multi-generational project such as this. It's a grand, sweeping plot, but there are extremely tense and exciting scenes as well. It's a thought provoking book, extending the themes of classic science fiction writers of the past like Arthur C Clarke, Isaac Asimov and Robert Heinlein.