Michael Bommes was an outstanding scholar and an enormously influential figure in the field of migration studies. With a characteristically German background in sociology – being heavily influenced by the theory of Niklas Luhmann – he was able to translate and export complex ideas across his extensive network of research collaborators and students throughout Europe, Turkey and North America. Michael himself had a strong impact on German sociology, contributing to important theoretical innovations and the opening up of new areas of research. He was also pivotal in initiating collaboration among researchers and policymakers both within Germany and at the European level. His scholarly interest had an unusually broad sweep, from linguistics and philosophy to economics and organisation theory.

In mid-2010, Michael was faced with the prospect that he may be unable to fight his illness. At the suggestion of the editors, he began to develop the idea of publishing a book that would disseminate his contributions on immigration and integration to a larger, English-reading audience. As colleagues enjoying a long-standing friendship with Michael, who have gained much from his wise advice and unflagging support, we were honoured to carry through this project. Michael put a lot of energy into the selection and presentation of the articles in this, his last book. He saw the final manuscript before he died on 26 December 2010.

In Michael, we lost a friend with a great sense of loyalty and humour, but also a passionate interlocutor with broad knowledge in many fields, from Schubert to the Bundesliga. We miss his sonorous voice, his sharp wit and ironic insights and not least his enjoying a well-earned pint after an intense research discussion or seminar.

Our acknowledgements go to all those who were close to Michael and who helped make this book possible. We thank Sigrid Pusch, who managed his office and helped us in numerous ways to prepare the manuscript at the project's onset. We are particularly indebted to Andrea Lenschow, Michael's companion in life, and to Andreas Pott, his successor at the University of Osnabrück. Both offered crucial comments and precious advice during the production of this edition.