The geosciences, particularly numerical weather prediction, are demanding the highest levels of available computer power. The European Centre for Medium-Range Weather Forecasts, with its experience in using supercomputers in this field, organises every second year a workshop bringing together manufacturers, computer scientists, researchers and operational users to share their experiences and to learn about the latest developments. This book reports on the November 2000 workshop. It provides an excellent overview of the latest achievements in, and plans for the use of, new parallel techniques in meteorology, climatology and oceanography.