EU Cohesion policy, along with support for agriculture and rural development, is one of the main items of EU spending. As such, the performance of the policy has come under increasing scrutiny. Perhaps surprisingly, however, past attempts to assess the effectiveness of the EU’s have proved to be highly ambivalent. This book examines the long-term achievements of Cohesion policy from 1989 to 2012 and draws out the main policy implications. Originally undertaken for the European Commission by the authors, this major longitudinal study adopts an innovative approach to assessing the effectiveness and achievements of this policy, building on case studies of 15 regions from different parts of Europe. The research provides policy lessons for the 2014-20 period and post-2020 EU Cohesion policy.