Add to ORKGThe "Geography of Innovation" is based on the desire to give empirical foundations to the explanations behind the pronounced spatial polarisation of the innovation activities. It focuses on an attempt to measure the spatial dimension of knowledge externalities, in order to reveal their role in the organisation of research systems. The aim of this paper is to survey this empirical literature in order to highlight the main results interesting for the innovation policy. This analysis emphasises one main role of technology policy : supporting the institutions which generate knowledge and learning. These are found at various territorial levels, especially within the European Union. Here attention is drawn to the regional intervention level