Fernando Casal Bértoa is an Assistant Professor in the School of Politics and International Relations at the University of Nottingham (United Kingdom). He is member of the OSCE/ODIHR “Core Group of Political Party Experts”. He is also Co-chair of the Council for European Studies’ Research Network on “Political Parties, Party Systems and Elections” as well as Research theme director at the Nottingham Interdisciplinary Centre for Economic and Political Research. His work has been published in European Journal of Political Research, Sociological Methods and Research, West European Politics, Party Politics, Democratization, European Constitutional Law Review, among others. Currently he is co-writing a book for OUP titled Party System Closure: Alliances and Innovations in Europe between 1848 and 2016".