There was little science policy in the past. Science and technology developed at their own pace. Science policy is now required, not just on grounds of the cost of science, but also because problems of esthetics and of environmental externalities are raised. There are also questions posed by the recruitment of scientists, the structure of research and, above all, priorities in scientific development. There has also to be an analysis of the level—regional, national, plurinational, worldwide—at which decisions on science should be taken. If this is not done through science policy, decisions will be taken entirely haphazardly.