This is a story of an intersteller colony ship that has problems in route to their destination and has to stop at a star for refueling. It is a great idea, somewhat along the E-ship idea that this group played with a while back. But, I don't buy the major premise that leads to all the conflict. All I could think of while reading the book was - why are they doing that? At least it needed a lot more setup to for me to believe that they would behave as they do. To me it seemed that the book spent a lot of time leading up to the climax and then solved it in one chapter, as if a time deadline or word limit was reached. If you're a Niven fan get this from a library but don't spend your money, especially on the hardback. Actually I think the prequel would be more interesting - why did they leave earth and what was the problem they had.

SPOILERS The colonists create and terraform a moon as a site to create antimatter fuel. To be able to do that they have children with the plan of abandoning them after the fuel is created. That is what I can't believe - that they will leave theri children to certain death.