The NATO Science Committee and its subsidiary Programme Panels provide support for Advanced Research Institutes (ARI) in various fields. The idea is to bring together scientists of a chosen field with the hope that they will achieve a consensus on research direc tions for the future, and make recommendations for the benefit of a wider scientific community. Attendance is therefore limited to those whose experience and expertise make the conclusions significant and acceptable to the wider community. Participants are selected on the basis of substantial track records in research or in the...