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spectacular growth of modern computer and telecommunications industries and, consequently, to the information revolution.

For many years after the invention of the transistor, the major intellectual challenge facing researchers in condensed-matter and materials physics was to understand the physical properties of nearly perfect single crystals of elements, simple compounds, and alloys. Most of these materials occur in some form in nature. On a basis of increased knowledge and powerful new synthesis techniques, today's condensed-matter and materials physics is directed toward creating entirely new classes of materials—so-called "artificially structured" materials—that do not exist in nature and whose sizes reach all the way down to the atomic domain. At the same time, a growing number of researchers are using new theoretical and experimental tools to extend our understanding to much more complex forms of matter—high-temperature superconductors, multicomponent magnetic materials, semicrystalline polymers, and glasses. These tools are, in turn, giving greater insight into more complex phenomena like the fracture of solids and the continuous transition from liquid to glass in the process of cooling. Ever in view in current condensed-matter and materials physics are research opportunities presented by dramatic progress in the biological sciences. Condensed-matter and materials physicists are working with biological scientists to develop a new field of "physical biology" in which physics-based techniques and approaches are applied to the study of biological materials and processes.

Indeed, condensed-matter and materials physics is distinguished by its extraordinary interdependence with other science and engineering fields. It is a multifaceted and diverse interdisciplinary field, strongly linked to other science and engineering disciplines that both benefit from and contribute to its successes. Important examples of this collaboration include fullerenes (physics and chemistry), macromolecules (physics, chemistry, and biology), structural alloys (physics and materials engineering), and silicon technology (physics and electrical engineering). Condensed-matter and materials physics also has strong interrelationships to other branches of physics. Prominent examples include Bose-Einstein condensation (with atomic physics) and the fractional quantum Hall effect (elementary-particle physics). Its practitioners include those who discover and develop new materials, those who seek to understand such materials at a fundamental level through experiments and theoretical analysis, and those who apply the materials and understanding to create new devices and technologies. This work is done in universities, in industry, and in government laboratories. Advances in basic research inspire new ideas for applications, and applications-driven technological advances provide tools that enable new fundamental investigations. Technological advances provide new tools such as synchrotrons, neutron sources, electron microscopes, computers, and scanning-probe microscopes. These new tools are leading to new advances in the fundamental understanding of materials and to a wide-ranging impact on other fields—biology, chemistry, environmental sciences, and engineering.