Feersum Endjinn, by Iain M. Banks

A surreal futuristic tale of conspiracy in a high tech universe where people have several "incarnations" (you die, you go into a databank, you're reborn in flesh and blood with memories of your previous lives). Well written, highly imaginative, but can be quite a challenge if you're not patient enough: there are entire chapters narrated by this character with some kind of speech disorder that are written in some constantly changing phonetic lingo (for instance: feersum = fearsome, endjinn = engine). Just don't think that because you found "business" written as "bidnis" once it will always show up like that. The premises: a man is murdered up to his last life and goes to live in the "crypt", that virtual world or databank, only to discover that his assasination has something to do with a corrupt monarchy and an ancient race of superbeings that departed Earth a long time ago and left behind a technology that can prevent a cataclism that would wipe life out of the face of the planet.