Nanotechnology will make us healthy and wealthy though not necessarily wise. In a few decades, this emerging manufacturing technology will let us inexpensively arrange atoms and molecules in most of the ways permitted by physical law. It will let us make supercomputers that fit on the head of a pin and fleets of medical nanorobots smaller than a human cell able to eliminate cancer, infections, clogged arteries, and even old age. People will look back on this era with the same feelings we have toward medieval times--when technology was primitive and almost everyone lived in poverty and died young.

Besides computers billions of times more powerful than today's, and new medical capabilities that will heal and cure in cases that are now viewed as utterly hopeless, this new and very precise way of fabricating products will also eliminate the pollution from current manufacturing methods. Molecular manufacturing will make exactly what it is supposed to make, no more and no less, and therefore won't make pollutants.

When nanotechnology pioneer Eric Drexler first dared to publish this vision back in the early 1980s, the response was skeptical, at best. It seemed too good to be true, and many scientists pronounced the whole thing impossible. But the laws of physics care little for either our hopes or our fears, and subsequent analysis kept returning the same answer: it will take time, but it is not only possible but almost unavoidable.

The progress of technology around the world has already given us more precise, less expensive manufacturing technologies that can make an unprecedented diversity of new products. Nowhere is this more evident than in computer hardware: computational power has increased exponentially while the finest feature sizes have steadily shrunk into the deep submicron range. Extrapolating these remarkably regular trends, it seems clear where we're headed: molecular computers with billions upon billions of molecular switches made by the pound. And if we can arrange atoms into molecular computers, why not a whole range of other molecularly precise products?

It has taken decades for the bulk of the research community to accept the feasibility of this vision. But when the President of the United States in January 2000 called for a US $500 million National Nanotechnology Initiative, we knew nanotechnology had reached critical mass.