It's a standard SF theme, isn't it: while the whole galaxy is teeming with intelligent life, this is especially true of its core, where the stars are packed more densely, and where live the Elder Races. In this book (and its prequel A Deepness in the Sky
), Vinge has turned that idea on its head. Here the galaxy consists of the central Unthinking Depths, where intelligence fails; the layer around this, which includes Earth, is called the Slow Zone: intelligent beings exist but computers are stupid. Further out is the Beyond, where electronics work better, and FTL travel is possible. From the galactic rim outwards is the Transcend, where thinking machines can become self-aware, and where a race may go to transcend into a Power of unimaginable intellectual ability. Of course Powers don't have to be nice, and every so often a malevolent one preys on the races of the High Beyond. Indeed it is suspected that the Zones were set up by an ancient Power to protect their untranscended forebears; and perhaps to ensure an unreachable source of new races who can then make their way upwards to civilisation.
Mankind meandered through the Slow Zone for many centuries before a few broke though to the Beyond. They remain insignificant in galactic terms, but have a world or two of their own as well as enclaves on many others. One small colony comes across an ancient archive in the near Transcend and restarts a self-aware program that turns out to be predatory. It easily outwits the humans and takes them over, and then starts on the neighbouring Powers. Fortunately, in the archive there is also a program that may be an antidote. Unfortunately, it gets loaded onto an escape ship that ends up on a primitive world in the low Beyond.
This is a long book: the above description covers barely more than the prologue. I felt it a bit too
long in parts; in particular, there is an extensive subplot involving the local politics of the Tines, the indigenous population of the world where the escape ship lands. Its tendency at times to drag isn't helped by the characterisation, which is only OK; and also I think by a consequence of the main plot, which has frequent bouts of death or enslavement of trillions of sentient beings. In fact this book must set a record for the quantity of fictional fatalities and destruction; yet because this mostly happens off-screen to people we've not met, it's impersonal and ungripping.
This is a galaxy full of alien races, and we get to meet several of them. In the physical sense they are done well, especially the Tines. These wolf-like beings are halfway to being hive creatures: a Tine 'person' consists of between 4 and 8 individual component bodies which communicate by ultrasound to generate a single thinking entity. The consequences of this are well explored: for example, two Tines cannot get too close to each other without their thoughts clashing, resulting in temporary loss of intelligence for both. Even better is Vinge's exploration of the meaning of personality in these circumstances. As one body component ages and dies another can be added, but usually with such an alteration in the gestalt that it becomes a different person. The result is one of the most alien-seeming aliens in SF; except that personality-wise they aren't: Vinge makes them feel far too human; shut your eyes and you could be reading about a man.
My other criticism concerns the plot resolution. On the face of it, this depends on too many close shaves and contrived coincidences. Look harder though and a deeper hole appears: Vinge implies, or at least doesn't rule out, the notion that the antidote program was able to manage perfectly well by itself, and the rescue party only made the denouement more focused. If so, too much of what went before becomes irrelevant.
These faults are by no means fatal, but they are enough to knock one star off the book's rating. Which is a shame, as the setting is the best I've come across for a long time, and the book is the most inventive. Certainly it's one of the more deserving Hugo winners of recent years. Everyone with any interest in epic space opera should read it.