Public policy spanning a broad range of contexts, ranging from the European Union, to states, cities and local communities around the globe, has turned to entrepreneurship to provide the engine for economic growth, competitiveness in globally linked markets, and jobs. This book explains why entrepreneurship has emerged as a bona fide instrument of growth policy. The knowledge spillover theory of entrepreneurship suggests that entrepreneurship provides a crucial mechanism in the process of economic growth by serving as a conduit for knowledge spillovers. Investments in new knowledge and ideas may not automatically spill over and result in commercialization, as has typically been assumed in models of economic growth. Rather, the existence of what is introduced as the knowledge filter impedes the spillover and commercialization of investments in new ideas and knowledge. By penetrating the knowledge filter and facilitating the spillover of knowledge that might otherwise not be commercialized, entrepreneurship provides the missing link to economic growth. This new focus of entrepreneurship as a conduit transmitting the spillover of knowledge generates a series of theoretical propositions, involving not just the impact of entrepreneurship on economic performance and growth, but also the very nature of entrepreneurship. The theoretical propositions range from positing that entrepreneurial opportunities are not exogenously given but rather endogenously and systematically created by investments in new knowledge and ideas, to the importance of geographic proximity between entrepreneurial activity and knowledge sources, the impact of location on entrepreneurial performance, and the new roles for board, managers and modes of finance in entrepreneurial firms accessing and absorbing knowledge spillovers. These propositions are subjected to systematic econometric scrutiny and verification using both aggregate data to analyze the links between entrepreneurship and growth, as well as firm-level data to analyze the impact of knowledge spillover on entrepreneurial location, performance, boards, managers and mode of finance. The resulting empirical evidence supports the knowledge spillover of entrepreneurship not only by linking entrepreneurship to economic growth and performance, but also by identifying how the organization and strategy of entrepreneurial firms are influenced by the need to access, absorb and commercialize external knowledge spillovers. The book concludes that the new millennium may not be so much about the process of Joseph Schumpeter's creative destruction, where entrepreneurial startups displace and ultimately drive incumbent company's out of business, but rather characterized by creative construction. Globalization and its concomitant outsourcing and offshoring is the source of the "destruction", especially in terms of lower skilled jobs. By contrast, in the 21st century global economy, entrepreneurship is constructive by commercializing investments in knowledge and ideas that might never have been commercialized but ultimately result in growth, global competitiveness and employment. Thus, the emergence of entrepreneurship policy can be interpreted as the attempt to generate entrepreneurial based economic growth by creating an entrepreneurial economy.

and Feldman, 1996 or Audretsch and Stephan, 1996) show that unformalized knowledge may playa major role in the innovation of new products. Now if unformalized knowledge is communicated personally, distance will be an important variable in this process, since the intensity of contacts between persons can be expected to be negatively correlated to the distance between them. In the discussion of section 3.3.1 (page 42) we saw that it was this aspect of localization that Marshall had in mind when he was alluding to "local trade secrets."4 Note that if this spatial dimension of communication between agents exists, it is possible to transfer it to regional aggregates of agents: the closer two regions, the more they will be able to profit from the respective pool of human capital (R&D-output etc.) of the other region. This argument gives a spatial 5 interpretation of the literature on endogenous growth. Now if these spillovers have a spatial dimension then it follows from the discussion in chapter 3 that they will be one driving force in the dynamics of agglomeration. With the model to be developed in this chapter I will investigate the hy pothesis that it is these forces of agglomeration (i.e. spatial spillovers of nonrival goods or foctors) that are responsible for the inhomogeneous pattern of growth con vergence. To analyze this phenomenon, I consider different types of regional aggregates and different distances in the model."