Prof. Dr. Betina Hollstein studied sociology at Philipps Universität Marburg and at the Free University, Berlin. She received her doctorate degree at the Free University, Berlin. Hollstein has been lecturer and researcher at the Universities in Berlin (Free University, Humboldt University), Munich and Mannheim, before she was appointed as professor of sociology at the University of Hamburg. Currently Betina Hollstein is professor of sociology at the University of Bremen. She is acting director of the SOCIUM - Research Center on Inequality and Social Policy at the University of Bremen. Besides, she is a member of the executive board of the German Sociological Association and a member of the board of directors of the International Network for Social Network Analysis (INSNA). Her research interests include social networks, sociology of the life-course, social inequality, and methods of empirical social research.Prof. Dr. Wenzel Matiaske studied Sociology, Political Science, and Economics at Philipps Universität Marburg and Public Administration at the German University of Administration Sciences Speyer. He worked as Research Assistant at the Universities of Paderborn and Mainz and held positions as Assistent Professor (1991-1998, Technische Universität Berlin), Acting Professor (1998-2000, University of Paderborg) and Full Professor of Business Administration at the International Institute for Management of Flensburg University (2000-2008). He is currently Professor at Helmut-Schmidt-University / University of the Federal Armed Forces, Hamburg. Furthermore, he is associated as Research Professor with the German Socio-Economic Panel Study (SOEP) at the German Institute for Economic Research (DIW), Berlin. Prof. Dr. Kai-Uwe Schnapp studied Political Science and Public Administration in Berlin and Minneapolis. He worked as Junior Research Fellow at the Social Science Research Center Berlin (WZB) and as postdoctoral researcher at the Otto-Friedrich-University Bamberg and the Martin-Luther-University Halle-Wittenberg. He currently is Professor for Political Science, especially Research Methodology at the University of Hamburg.