The creation and application of new technologies in the form of new products or new processes is increasingly becoming a collective effort in which firms, universities and research laboratories as well as public and other institutions at various spatial scales are engaged. Some of these "networks" are international or even global, such as strategic alliances and R&D joint ventures, which are undertaken to mobilize complementary assets and to provide distant market access. However, it is at the the local and regional level that the development of technology-based firms is most often stimulated. The example of the Greater Boston region shows that these local links are particularly relevant for newly emerging industries such as the computer industry in the 1960's or the biotechnology industry in the 1980's. Relevant linkages include those to universities and research institutions as well as those to venture capitalists, business services, specialised suppliers and customers. Since very specific knowledge bases, firms and institutions are involved, only few regions of a country can develop such high technology networks. As the industries mature, not just the markets but also the supplier and collaborative linkages become international and global, and the embeddedness of these networks into the region therefore becomes less important.