Unbounding the Future: the Nanotechnology Revolution by Eric Drexler and Chris Peterson
"Nanotechnology. The science is good, the engineering is feasible, the paths of approach are many, the consequences are revolutionary-times-revolutionary, and the schedule is: in our lifetimes. But what? No one knows but what. That's why a book like this is crucial before molecular engineering and the routine transformation of matter arrives. The technology will arrive piecemeal and prominently but the consequences will arrive at a larger scale and often invisibly.
Perspective from within a bursting revolution is always a problem because the long view is obscured by compelling immediacies and the sudden traffic of people new to the subject, some seizing opportunity, some viewing with alarm. Both optimists and pessimists about new technologies are notorious for their tunnel vision."