This Background is written for nontechnical readers. Those with more technical questions may wish to examine the technical literature cited in other Foresight publications. This Background is not copyrighted and may be reproduced freely. What is nanotechnology? Nanotechnology is an anticipated manufacturing technology giving thorough, inexpensive control of the structure of matter. The term has sometimes been used to refer to any technique able to work at a submicron scale; here it is used in the more usual sense of general control of the structure of matter on a nanometer scale--that is, a broad ability to control the arrangement of atoms. This ability will require development of devices termed assemblers. (A micron is a millionth of a meter; a nanometer is a billionth.) What is an assembler? An assembler will be a device having a submicroscopic robotic arm under computer control. It will work by applying reactive molecular tools to a workpiece, building objects molecule by molecule. Assemblers will pop atoms into place with complete precision, enabling them to build virtually anything possible under natural law. With proper programming, materials, and so forth, assemblers will be able to build copies of themselves, that is, to replicate. Will developing nanotechnology require new scientific discoveries? The basic properties of atoms and molecules are already well understood, though routine research will be part of the development process. The existence of molecular machines in nature shows that machines at that scale are physically possible. No new fundamental science is needed; nanotechnology will be an engineering advance. This makes it foreseeable, unlike future scientific discoveries. How will nanotechnology be applied? Improving the ability to control matter has long been a major aim of technology. The consequences of assembler-based manufacturing will be enormous in areas as diverse as computation, medicine, and the environment. How will nanotechnology change manufacturing? Because they will be able to copy themselves, assemblers will be inexpensive. We can see this by recalling that many other products of molecular machines--firewood, hay, potatoes--cost very little. By working in large teams, assemblers and more specialized nanomachines will be able to build objects cheaply. By ensuring that each atom is properly placed, they will manufacture products of high quality and reliability. Left-over molecules would be subject to this strict control as well, making the manufacturing process extremely clean. Even if assemblers put every molecule in place perfectly, won't they get out of place later, making nanomachines unreliable? Radiation can break bonds and misarrange atoms within a device. Such defects can be dealt with in two ways: (1) by using designs in which when one part fails, another takes over; engineers call this redundancy, (2) by using repair devices left within the object to make molecular repairs when needed. Without such precautions, molecular machines would eventually break down and stop working. How will nanotechnology be used in computation? Assembler-based manufacturing will enable the construction of extremely small computers. The equivalent of a modern mainframe computer could fit into a cubic micron, a volume far smaller than that of a single human cell. Once such nanocomputers have been designed and the technology is in hand, building them will be inexpensive, enabling us to use many of them at once. A laptop computer could then have more power than all the computers in the world today put together. How will nanotechnology be used in medicine? Assembler-based manufacturing will provide new tools for medicine, making possible molecular-scale surgery to repair and rearrange cells. Since disease is the result of physical disorder--of misarranged molecules and cells--medicine at this level should be able to cure most diseases. Mutations in DNA could be repaired, and cancer cells, toxic chemicals, and viruses could be destroyed through use of medical nanomachines, including cell repair machines. What is a cell repair machine? A cell repair machine would be a device having a set of minuscule arms and tools controlled by a nanocomputer; the whole system could be much smaller than a cell. A repair machine could work like a tiny surgeon, reaching into a cell, sensing damaged parts, repairing them, closing up the cell, and moving on. By repairing and rearranging cells and surrounding structures, cell repair machines could restore tissues to health. Cells build and repair themselves using molecular machines; cell repair machines will use the same principles. The main challenge will be to orchestrate these operations properly, once assemblers are able to build suitable tools. How will nanotechnology be used to benefit the environment? By giving thorough control of matter, nanotechnology will enable us to end chemical pollution: any waste atoms could be recycled, since they could be kept under control. By reducing the cost of environmental cleanup and freeing land area from industrial uses, assembler-built products should aid environmental restoration. For example, even the immense tonnage of excess carbon dioxide in the atmosphere--a chief cause of greenhouse warming--could be swiftly and economically removed. What effects will nanotechnology have on the economy? It will fundamentally revolutionize most industries, and has been compared in importance to humanity's taming of fire. The Industrial Revolution pales in comparison. Because assemblers will be able to build copies of themselves quickly, using inexpensive materials, little energy, and no human labor, a single assembler can be used to make billions. Once we have software to program assemblers to make consumer goods, each household could use an assembler system to produce goods cheaply and quickly. Manufacturing, mining, transportation, and other industries will change radically. Individuals will be able to make at home much of what they need, reducing the need to transport goods. This should encourage decentralization. Who is developing nanotechnology? Progress toward nanotechnology is being made in many laboratories around the world, notably in the U.S., Japan, and Europe. Three fields of work are seen as most relevant: protein design, biomimetic chemistry, and atomic imaging and positioning. Major advances in protein design have been made in the last two years, including Du Pont's successful effort to design a protein to fold predictably. Biomimetic (or supramolecular) chemistry is bringing some of the characteristics of natural molecular machines to new, designed ones. Individual atoms are being seen and, increasingly, positioned using new scanning probe microscopes. Progress in the latter two fields has merited two recent Nobel prizes. These efforts will be aided by advanced molecular modeling software, which continues to improve. Work in these fields is being pursued largely for its short-term benefits, rather than as part of a long-term development plan. Many researchers have not considered the connection between their work and the eventual emergence of nanotechnology. Research in Japan, however, seems to have a longer-term motivation. How will nanotechnology arrive? The three paths of protein design (biotechnology), biomimetic chemistry, and atomic positioning are parts of a broad bottom up strategy: working at the molecular level to increase our ability to control matter. Traditional miniaturization efforts based on microelectronics technology have reached the submicron scale; these can be characterized as the top down strategy. The bottom-up strategy, however, seems more promising. The ultimate goal--thorough, inexpensive control of the structure of matter--remains the same regardless of the path used to reach it. When will nanotechnology be achieved? While exploratory engineering techniques let us sketch what nanotechnology will make possible, building firmly on engineering experience and the principles of natural law, these techniques give no way to calculate implementation dates. That will depend on which groups decide to pursue the goal directly, when the decisions to do so are made, and how much funding is put into the projects. Since the various paths are being pursued for their own intrinsic benefits, rather than as an explicit nanotechnology development program, progress will continue even in the absence of a deliberate effort. Any time estimate can be at best an informed guess; common estimates fall in the 10-50 year range (the shorter estimates are often produced by those more familiar with Japanese research objectives). Powerful technologies generally have great potential for abuse; is this true of nanotechnology? A technology that can build sophisticated products quickly and inexpensively could be used to quickly build a vast arsenal of powerful weapons. Further, new types of weapons might be developed, combining features of today's chemical and biological weaponry with greater control and hence greater military usefulness. Should we be concerned about runaway replicators? It would be hard to build a machine with the wonderful adaptability of living organisms. The replicators easiest to build will be inflexible machines, like automobiles or industrial robots, and will require special fuels and raw materials, the equivalents of hydraulic fluid and gasoline. To build a runaway replicator that could operate in the wild would be like building a car that could go off-road and fuel itself from tree sap. With enough work, this should be possible, but it will hardly happen by accident. Without replication, accidents would be like those of industry today: locally harmful, but not catastrophic to the biosphere. Catastrophic problems seem more likely to arise though deliberate misuse, such as the use of nanotechnology for military aggression. Given these problems, should nanotechnology be stopped? This seems to be a false alternative. Many paths lead to nanotechnology, whether through chemistry, biotechnology, or physics. Thousands of companies and dozens of countries are pursuing these paths and reaping benefits along the way. This competition ensures that it will be developed, regardless of whether any one group, country, or alliance favors it or opposes it. Many groups are in a position to press forward, in the open or in secret; none are in a position to say no and make it stick, worldwide and forever. How can abuse of the technology be minimized? Ideally, the race for early breakthroughs will be won in a country or group of countries firmly under democratic control, where a free press and public scrutiny can help prevent abuse. Broadly-based international cooperation seems clearly desirable if we are to minimize the chance of friendly competition turning into hostile competition and then an unstated arms race. This makes continued friendship with Japan of great importance. How is the concept of nanotechnology being received by scientists and engineers? Most scientists and engineers fall into the following categories: (1) those who have had no exposure to the concept, (2) those who have had exposure to the idea primarily through the media, and have not yet examined it seriously, (3) those who have examined nanotechnology as a technical issue and have found it reasonable. It is difficult to find credible scientists who have studied the case for nanotechnology and have a substantive technical objection. Scientists study nature and engineers design products, so both are typically unfamiliar with the issues involved in studying future technologies. Generally, those with at least some technical knowledge of biological molecular machines are quickest to evaluate the concepts favorably. Those who have heard only brief, colorful, second-hand explanations are more likely to comment unfavorably; for this reason, the Foresight Institute sponsors technical meetings and helps direct researchers to technical publications. How is discussion of nanotechnology being received by scientists and engineers? Some researchers feel that discussion of new technical concepts such as nanotechnology should be restricted to the technical research community until they have been actually developed, fearing that premature exposure may lead to confusion, and perhaps to inappropriate and premature regulation. The Foresight Institute, however, believes that powerful technologies deserve early and thorough consideration, to help us maximize benefits and minimize problems. Involving the technical community in this process is essential. Should government be involved at this point? Public policy makers rely on the technical community to provide raw data needed to construct technology policy, answering such questions as: Is this technology possible? How easy or difficult will it be, from a technological perspective, to guide development? The technical community is still examining these questions. It will be years before a clear message can be delivered to policy makers for use in decision making. Until a consensus is closer on the basic technical issues, making policy would be premature. Frustrated policy makers can speed this process by funding technical meetings aimed at critically evaluating the feasibility of nanotechnology. How did the idea of nanotechnology emerge? Work done early this century clarified the nature of matter and atoms, showing how atoms combine. Research by chemists in the 1950s showed the workings of natural molecular machines. In a 1959 talk, physicist Richard Feynman proposed that tiny robots might be able to build chemical substances. At MIT in 1977, as an outgrowth of studies of naturally-occurring molecular machines, Eric Drexler developed the essentials of the current concept of nanotechnology. These ideas were first presented in a scientific journal in 1981, and in a book in 1986. He taught the first course on the subject at Stanford University in 1988. Where is more nanotechnology information available? The Foresight Institute publishes on both technical and nontechnical issues in nanotechnology. For example, students may write for our free Briefing #1 Studying Nanotechnology. The Foresight Institute's main publications are the Update newsletter and Background essay series. Our Update newsletter includes both policy discussions and a technical column enabling readers to find material of interest in the recent scientific literature. Most members join the Foresight Institute after having read Engines of Creation (by K. Eric Drexler, Anchor Press/Doubleday, 1986). This book, written to be accessible to a general audience, addresses many of the topics above. New books relevant to the topic are reviewed in Update.