High-Rise - J.G. Ballard

A dark sort of social experiment in novel form, written in an unsettlingly matter-of-fact style without much authorial comment at all. It's masterful the way it unfolds increasing levels of violence and depravity, moving imperceptibly through stages of regression until the high0rise residents are living as savages. There's a strain of humour in it too, which simultaneously stops it becoming too grim or po-faced but serves to make the really horrific bits all the more shocking. A very powerful book.