The conditions for security in Europe in the 21st century differ from those in the second half of the 20th century. The consequences of the East-West conflict no longer determine the security agenda. Due to the pan-European process of integration and cooperation, European countries have the chance of a future together in an "area of peace, freedom, security and justice". However, the security situation in Europe is determined by new threats and risks. Comprehensive security means that external and internal as well as civilian and military security aspects are closely linked. It goes beyond traditional security issues and includes, inter alia, instruments of economic, social, and health policy. In addition, today's threats are of cross-boarder nature: Threats like attacks on the security of IT systems, organized crime, and climate change appear to be solvable mainly through international cooperation. Thus, the role of international organizations is becoming more important. The 11th Network Conference analysed the existing security architecture of Europe in the above mentioned political areas. The contributions can be found in this publication.