A fast-paced techno-thriller, and very impressive for a first novel. I've placed the author, Daniel Suarez, on my "gotta read more" list. Suarez is an ex-IT consultant and seems to know whereof he speaks.
The book opens with two unusual deaths. In one, a motorcyclist is gorily garrotted by a cable appearing suddenly in his path. In the second, a programmer is messily electrocuted when trying to enter a computer server room. It turns out that these are homicides, both victims employees of Cyberstorm, a computer game company. And (insert ominous music here) both crimes were carried out—over the Internet! And they are apparently the doing of Matthew Sobol, the recently deceased head of CyberStorm. Yes, recently deceased. Sobol lives on as the Daemon, an insidious program distributed worldwide via the company's popular games. (The term "daemon" refers to processes that most modern computer operating systems run behind the scenes to perform various useful tasks like printing, sending mail, access databases, etc.)
No spoilers here, but the Daemon has a pretty interesting goal, and doesn't really care who it has to kill, maim, or blackmail to accomplish it. (It never heard of Asimov's Laws of Robotics.) Through foul means, it recruits human allies. And the body count keeps going up. A small number of valiant good guys oppose the Daemon, but they always seem to be a couple steps behind.
Consumer note: there's a sequel. If you read this, you'll probably need to read the next one.
Quibble: Suarez's prose is kind of clanky in spots. A lot of hardware (weaponry, computer stuff, cars) is brand-named, which can get a little tedious. Just minor glitches in a very readable effort.