IMISCOE owes a lot to Michael Bommes. It is no surprise that he was a key figure in the groundwork and establishment of the IMISCOE Network of Excellence. Michael took on several important roles in our organisation. He led the research cluster on economic integration. As director of the Institute for Migration Research and Intercultural Studies (IMIS), he hosted the Second Annual IMISCOE conference at the University of Osnabrück. To this day, Michael remains irreplaceable on the IMISCOE Board of Directors, where his modestly offered interventions and proposals were as constructive as they were brilliant. When the Network of Excellence transformed itself into the current IMISCOE Research Network, his support and advice were always to be found.

Although he passed away on 26 December 2010, Michael knew that IMISCOE hoped to bring together the fruit of his labour, publishing it as a whole. Even during his protracted period of illness, he continued to work as much as possible. Among other things, he sharpened and updated some of his earlier articles, which now form part of this manuscript.

This publication of his major contributions to the field of migration and integration studies is a way of honouring Michael, our colleague. At the same time, it is meant to serve the scientific community by making the nationally acclaimed research of Professor Bommes available and accessible to a wider, international readership. It was easy to carry on the momentum of such a scholar, motivated and engaged till his last breath.