Computers are playing an integral role in both experimental and theoretical condensed-matter physics: In laboratories they are being used to control experiments as well as to gather and analyze data; in theoretical studies they provide the means for making detailed predictions for realistic models, for exploring systems that cannot be realized in the laboratory, such as four-dimensional systems undergoing phase transitions or materials under extreme conditions of pressure or temperature, and for complicated symbolic manipulations. Often computers provide an essential link between experiment and theory, allowing experimentalists to test critically theoretical predictions and allowing theorists to make predictions for realistic models.