Altered Carbon   by Richard Morgan

A story which could only be told in a universe where human souls can be freely replicated, stored and moved between bodies, both artificial ones and real ones (termed ``sleeving''). A very rich three hundred year old man killed himself and he doesn't know why (he now has a new sleeve which is a facsimile of his original one, and his soul has been recovered from a time shortly before his previous death). The detective is an elite agent of a galactic organisation, pulled out of an imposed period of storage for crimes deniable to the state, and sleeved into the body of a local policewoman's lover.

It is an amazingly inventive backdrop on which to weave a story in the first place. To be fair, the story itself is very simple once the murderer is revealed, and there is no point trying to second-guess the book as the first part, like all detective novels make all suspects equally possible, and the second part does not make any real secret of who the culprit is.

The story aside, the book is absolutely outstanding for its exploration of the social impacts of having the re-sleeving technology. The detective is not on his own planet, and his exploration of the world is also the reader's exploration of that world. There is no info-dumping; the reader learns about the environment as the detective finds his feet in that environment. The reader also becomes familiar with the etiquette, and vices and taboos surrounding the use of the available sleeving technology, and gets to inhabit the city, particularly the less savoury aspect of the city in which the action mostly takes place. It is a perfect cross between Asimov's I, Robot and Mieville's Perdido Street Station: a crime particular to the universe, and a universe small and cosy enough to be described fully in loving detail.

But the very cleverest thing about this book is the reasoning for the crime, and the ingenious way the detective explains it (he is forced to abandon his true pursuit of the truth in order that he can leave the planet with the best overall outcome). Very simply (I said the story was not that strong) the man had witnessed a murder in an expensive whore-house, and the owner wanted his memory of that erased to avoid any possible conflict in future. The fiction created by the detective: the rich man had his soul infested by a virus which would kill off his soul if it was allowed into storage (he would never be able to retrieve an uncorrupted version of himself), and so he must have killed himself before the next update of his soul to storage; in effect, he had to kill himself to save himself. Absolutely brilliantly worked out piece of plot, and in itself deserving the maximum possible star rating. The sublime inventiveness of the universe and the atmospheric descriptions of the places and people are generous bonuses on top of that.