Look to Windward by Iain M. Banks
ISBN: 1841490598
The culture seems to be a metaphor for western liberalism. A vast sprawling technologically advanced outflowing of humanity into the cosmos. Somewhat superscillious, somewhat decadent, but with their hearts in the right place. In the book, we learn of a plot by an agrieved race to kill billions in retribution for an accidental war caused by the culture. In a well paced thriller we discover whether the Hub of Masaq, a computer intelligence of unimaginable power can survive both the suicidal attack of a Chelgrian asassin and its own sense of guilt for past killings.