'Peter Mair focused on building sophisticated political arguments, significantly linked to existing theoretical knowledge and often innovating it, solidly grounded in a detailed knowledge of cases and always open to revisions and refinement. Even in his most academically sophisticated analyses, Peter always started and eventually concluded with a reference to, and a concern for, important substantive political questions and their implications for citizens, leaders, and politics - As most obituaries published shortly after his death have underlined, Peter made a great contribution to the development of succeeding generations of scholars. In the countless conferences, workshops and colloquia he organised, the participation of young, and often very young, scholars was always very significant. He also did much to alert later generations to the contributions of earlier ones, as in his reader The West European Party Systems (1990), his constant confrontation with the work of earlier scholars in his chosen field of party studies, his bringing to light the unpublished work of Sartori, and his pressure on older scholars to put together a volume of their writings. [Mair's] willingness to devote time to read, comment, and help other people's work is witnessed by the frequency with which he was approached by the most different people. [he was held in] immense esteem among those who knew, encountered or simply contacted him - [this book] marks the stature of an intellectual who was certainly a leading scholar of party politics and European politics of the post-postwar generation, and whose work has been influential in the field for more than thirty years.' Stefano Bartolini, Peter Mair Chair in Comparative Politics, European University Institute Hans Daalder, Professor Emeritus, University of Leiden This volume's editor Ingrid van Biezen is Professor of Comparative Politics at Leiden University. She has previously taught at the University of Birmingham (UK) and Johns Hopkins University, and has held Visiting Fellowships at Yale University, the University of California, Irvine, and the European University Institute. She is a co-editor of Acta Politica, a former co-editor of the Political Data Yearbook and the author of Political Parties in New Democracies. Her current research focuses on political parties, party regulation, and democratic theory. She has published in, among others, the British Journal of Political Science, the European Journal of Political Research, the European Political Science Review, Government and Opposition, Party Politics, Perspectives on Politics, and West European Politics.