Someone asked me a few years ago how I would go about writing "modern" computer virii. I was heavy into AI and genetic software/genetic algorithms at the time, so I replied that I wouldn't but the most "modern" creation would be an "evolving" virus. It would be unpredictable and depending how its fitnesses were defined it could be very dangerous. This book describes one of the ways in which that type of "creation" could evolve into something very disrupting.
