Atoms and computers

The development of computer technology and of efficient algorithms has allowed the realistic simulation of condensed matter system. These calculations provide precious insight, replace difficult experiments, and predict new phenomenon. We shall illustrate the power of this approach with a number of exmples taken from different branches of science. However, in spite of remarkable progress much remains to be done to widen the scope of atomistic simulations, especially in areas like nanotechnology or biosciences. This requires new technical as well as conceptual tools in order to describe the complexity of the phenomena that contemporary science has to tackle. Avenues of progress will be presented.