Excession (Culture 4)

Excession, first published in 1996, is Scottish writer Iain M. Banks' fourth science fiction novel to feature the Culture. It concerns the response of the Culture and other interstellar societies to an unprecedented alien artifact, the Excession of the title.

The book is largely about the response of the Culture's Minds (AIs with enormous intellectual capabilities and distinctive personalities) to the Excession itself, and the way in which another society, whose systematic brutality horrifies the Culture, tries to use the Excession to increase its power.