The investigation presented in this book is based on the project funded by the German Research Foundation (DFG) within the priority program "Structural Change in Industrial Relations": "The Importance of Special and Precarious Employment Relationships for the Development of Industrial Relations in France and the Federal Republic of Germany." It was conducted from 1989 to 1992 at the Institute of Sociology of Philipps University Marburg and completed at the University of Duisburg. We would like to take this opportunity to thank all those who contributed to the progress and completion of the project, especially the experts and association representatives we interviewed, who made themselves available for sometimes very time-consuming discussions and from whom we received important material. We are indebted to them.