House of Suns by Alastair Reynolds

This story is set millions of years into the future and mankind has expanded around the galaxy in many expanding and collapsing empires. The only constants are the "lines", clone families who persist through the millennia travelling around the galaxy and possessing almost god like powers (the ability to dam a star for example). An attempt to wipe out one of the lines sparks off an enjoyable romp through big concept sci fi. Generally very good but the ending is weak in my opinion.