Many believe that nanotechnology will be disruptive to our society. Presumably, this means that some people and even whole industries will be undermined by technological developments that nanoscience makes possible. This, in turn, implies that we should anticipate potential workforce disruptions, mitigate in advance social problems likely to arise, and work to fairly distribute the future benefits of nanotechnology. This general, somewhat vague sense of disruption, is very difficult to specify – what will it entail? And how can we responsibly anticipate and mitigate any problems? We can't even clearly state what the problems are anticipated to be. In fact, when we move from sweeping policy statements to more concrete accounts, nanotechnology seems to bifurcate into two divergent streams: one is fairly continuous with current developments, extending extant science in a quantitative way; the other is radically new, and includes science fiction-like dreams of molecular manufacturing and assemblers, with their utopian (or dystopian) scenarios of absolute plenty (or runaway self-replication). In these cases, “disruption” takes on the valence of Huxley's brave new world.