Polish membership in the EU and the conversion of Polish-Ukrainian and Polish-Belarusian border, has undoubtedly influenced the relactions and co-operaction in the trans-border region. Therefore, it was important to analyse both the scale and the scope of these changes, as well as the new role of different astors in trans-border co-operaction. Hence, in this book, special attencion is given to finding the answer to the question of whether the enlarged EU will emerge as a "Fortress Europe" or as a "Golden Curtain".