This book is the result of intensive teamwork over a couple of years. Funded by the Max Planck Society, a research group on 'New Governance and Social Europe: Minimum Harmonisation and Soft Law in the European Multi–level System' was established at the Cologne-based Max Planck Institute for the Study of Societies. We are grateful to the Institute's Directors, Fritz W. Scharpf (until 2003) and Wolfgang Streeck, for their support of our work. From October1999 to September 2003, the research team collaborated face-to-face in Cologne. Co-operation has been continuing ever since then, with e-mails and phone calls serving to bridge the physical gap between the team members, who have all moved on to new jobs in different places all over Europe.

Directed by Gerda Falkner, the group of collaborators included three doctoral students who wrote their dissertation theses on specific aspects within the group's common theme. In his doctoral thesis, Oliver Treib examined the transposition of EU Directives. Focusing on Germany, the Netherlands, Ireland and the UK,he sought to establish the relative significance of the amount of policy misfit vis-à-vis other explanatory factors in determining domestic transposition performance (Treib 2004). After completing his thesis, he continued to work in the project team as a postdoctoral researcher. Miriam Hartlapp's dissertation analysed the transposition process and the enforcement structures in the southern and francophone member states, and the European Commission's enforcement policy (Hartlapp 2005).