This book won the Hugo Award for best science-fiction novel last year, and it was well deserved. I don't read a lot of science fiction any more (I keep saying that, I know), but Vernor Vinge is on the very short list of authors I try to catch as new stuff appears.
The novel is set mostly in San Diego, just a couple of decades from now, but the technological changes have been stunning. Nearly everybody "wears": contact lenses, ear implants, and smart clothing allow you to experience a convincing virtual reality of choice overlaid on actual reality. Combined with ubiquitous networking, this allows personal interaction with people from around the world, as if they were actually present.
Cheap, sophisticated technology is available to bad guys too. The immediate threat is a YGBM ("You Gotta Believe Me") brainwashing weapon, spread through a combination of bioengineering and networking. In a nice libertarian touch, the mastermind of this plot is a would-be for-your-own-good social engineer.
A mysterious cyber-presence assembles a very unlikely team to thwart the evildoers; most of the team have no idea what's going on. Members include a once-famous poet recovering from Alzheimer's, his plucky granddaughter, and a well-meaning remedial classmate from the local vocational high school.
It's a pretty good read, probably better if you're familiar with San Diego and the UCSD campus, where a lot of the action occurs. I was there long ago, and was awestruck by the Geisel Library; it has a pivotal role here. To paraphrase Dr. Venkman from Ghostbusters: generally, you don't see that kind of behavior from a major library building.
By sheerest coincidence, John Tierney has a column and a blog post up about Vinge and Rainbows End today. (With a picture of the library, currently behaving.)