No, I haven't mis-typed the title. There's no apostrophe, and one of the characters in the book has a little grump about it. The background and the people are in many ways far more interesting than the story itself. The world that Vinge has built has a fair amount in common with some of his other work, in particular the ubiquitous networked computing that he elsewhere calls "localisers". The theme of surveillance is also something that readers of, eg, A Deepness In The Sky, will be familiar with. And what's more, a lot of the background is a reasonable extrapolation from the present day. Networked computing is becoming ubiquitous; augmented reality is in use in some industries and being played with by hackers the world over; and of course the Surveillance State is growing a-pace, all in the name of Stopping Terror - a justification that they use in this book too. Thankfully the Secure Hardware Environment that Vinge postulates doesn't yet exist, and something similar has proven to be a failure in the market so far, but I'd not be particularly surprised if something like it were to appear again soon. So the story is firmly rooted in the present.
The actors are believable too, if pushed just a little to extremes. But such is the nature of heroes and villains in all fiction. As is often the case with good fiction, I was left at the end of the story wondering what their lives would be like afterwards.
There are a few problems though. The "belief circles" - something that other reviewers have described as a blend of wikipedia, second life and augmented reality - don't make much sense to me, and while they only play a minor part in the story, serving as a distraction the bad guy manipulates to keep the "good" guys away, they could have done with more fleshing out, in particular explaining why individuals choose to put so much effort into them. But the biggest problem is that to understand all that goes on you need to understand public key encryption and authentication. And virtually no-one does. I do though, so it didn't spoil my enjoyment of the story, and with the one caveat that you should be at least on speaking terms with public-key crypto, I recommend this book. The biggest disappointment was that it was all fiction - one of the "belief circles" that Vinge invents is based on the fiction of one "Jerzy Hacek" who unfortunately doesn't exist. Shame, cos the Librarians Militant sound wonderful.