This study provides an overview and assessment of the state of cross-border co-operation between European states in the geographical areas of Central, Northern and South Eastern Europe;  it applies the so-called SWOT methodology according to the specific parameters developed by ISIG to assess the extent and depth of cross-border co-operation. The first three volumes, previously published,  have dealt with the specific analysis of each macro-area. In the present volume, the first chapter deals with the methodology of the SWOT analysis and the second one with the theoretical design of the Euroregion. Addressing these two topics is important to understand the concepts and terms used in chapter three, dealing with the comparison of cross-border co-operation among the considered areas. This is followed by the identification of the most appropriate “strategy” recommended in order to achieve the best possible cross-border co-operation (removing obstacles, skipping threats, exploiting opportunities, healing weaknesses).