Thomas Kieselbach 1 Object and organisation of the study The present volume contains the first results of an international research project on youth unemployment and social exclusion describing the most up-to-date research of youth unemployment and health in six European countries. The project "Youth Unem­ ployment and Social Exclusion: Objective Dimensions, Subjective Experiences, and In­ novative Institutional Responses in Six European Countries" (YUSEDER) is supported by the Research Directorate General of the European Commission (DG XII) within the Targeted Socio-Economic Research Programme (TSER) of the 4th Framework Pro­ gramme. The YUSEDER research project tries to answer some crucial questions with regard to the risk of social exclusion associated with long-term youth unemployment. The European Commission launched a call for proposals looking for new know­ ledge of the key mechanisms linking the experience of long-term youth unemployment to various dimensions of social disintegration, conceived of in the theoretical frame­ work of social exclusion. In this context, not only the mechanisms exacerbating the stress of unemployment (vulnerability factors) but also the protective mechanisms pre­ venting or reducing the risk of social exclusion have to be taken into consideration. The second research question relates to new options of institutional and political inter­ vention and counteraction in different national contexts. These analyses will be underta­ ken in three Northern European countries (Sweden, Belgium, Germany) and three Sou­ thern European countries (Spain, Italy, Greece).