I'm more than a little fan of Vernor Vinge. So, I was quite happy to get this book. It's actually two novels in one - The Peace War and Marooned in Realtime. These are rather earlier works than A Fire Upon The Deep and it shows....
The Peace War is set in a world of massive die-back, where a world police controls the world through a form of physics which is able to instantaneously seal off bits of the world in impermeable spheres. The Peace Authority deliberately holds back progress to stabilise the world. Who stands to oppose them? Why, plucky libertarian Californian scientists! As a plot goes, it's rather less weak than it sounds, and does roll along fairly nicely.
Marooned in Realtime is a sort of sequel, although it doesn't really follow on in a traditional sense, being set 50 million years later. It's a very strange cross between murder-mystery novel and last-humans-alive-with-insane-tech novel. I was once foolish enough to read a (borrowed) Michael Moorcock book, and it's a bit The Dancers at the End of Time. And he skims around the whole Singularity thing. I'm not sure if it works, but again I'm happy to read it.
So, basically a good example of a decent author's early work. You can see some of the cool stuff in later books developing, but it's not all there yet. Interestingly, I'm not normally a fan of space opera, but his later books are much more so, while these are fairly earth-bound, and as he moves to grander scales his stuff gets better. Worth reading if you're a Vinge fan, but don't go running out to get them if you aren't. In that case, run out and get A Fire Upon The Deep instead.