In this book I seek to clarify what a mechanism-based explanatory strategy looks like. At the core of the approach is a set of mechanisms that specifies how individuals are influenced by those with whom they interact. Such mechanisms are not only the object of this book, they also explain why the book looks the way it does.

I have benefited greatly from interactions with numerous colleagues in Europe as well as in the United States. First of all I would like to thank Yvonne Åberg. Not only is she the co-author of one of the chapters, she has also served as a constructive discussion partner throughout this book project. Others who have made time to read and comment on the book include Peter Abell, Patrik Aspers, Filippo Barbera, Peter Bearman, Markus Berger, Michael Biggs, Raymond Boudon, Richard Breen, Magnus Bygren, Mohamed Cherkaoui, Christofer Edling, David Freedman, John Goldthorpe, Carl le Grand, Ann-Sofie Kolm, Fredrik Liljeros, Lars Lindahl, Renate Meyntz, Carina Mood-Roman, Krister Segerberg, Mattias Smångs, Ryszard Szulkin, Lars Udehn and Björn Wittrock. I am extremely grateful to you all.

I also have had the great fortune to be affiliated to several excellent academic institutions; the Department of Sociology at Stockholm University, the Swedish Collegium for Advanced Studies in the Social Sciences (SCASSS) and Nuffield College, Oxford. These institutions have allowed me to concentrate on my research for extended periods of time and have provided most stimulating intellectual environments.