One advantage of reading science fiction is that it forces you to confront the fact that the future will be unlike the past, due to things you're barely aware of. Of course, nanotechnology — the manufacture and use of molecules that function as machines — might turn out to be mostly a mirage, as fusion power has (so far) turned out to be. But if not, it looks like the biggest revolution in materials technology since the beginning of the Bronze Age, and it's not hard to imagine it bringing about changes as fundamental as those now being brought about by information technology. Interesting times.
As a piece of technical speculation on the marriage of nanotech with agent-based simulation, Michael Crichton's Prey is fascinating. (I can't say how good the science is, but Crichton has a reputation for getting it right.) As fiction, it's just hackwork; someone told me that Crichton used to be better as a novelist, which I hope is true. If what Neal Stephenson does is writing, Critchton's product is, as Scott Fitzgerald once said, just typing.