It is a fundamental structural characteristic of industrial economies that economic activities tend to co-locate, i.e. cluster in space. The study of clusters and clustering is today an integral part of many undergraduate and postgraduate studies in business administration, economics, economic geography, and urban and regional planning as well as a topic of research in these disciplines. At the same time, we can observe many governments at different levels in industrialized countries that have initiated cluster studies and introduced policies aiming at supporting existing clusters and stimulating the emergence of new clusters. The success of these policies has varied substantially but cluster policies seem to have become an integral part of the industrial and regional policies in industrialized countries.