With the stability of the European Union under threat and tensions between the national and supranational increasing, what will happen to the EU party system?For the internationalist European left, European integration and the role of transnational parties represent a central contention and concern. In May 2004, the European radical left, representing parties to the left of social democracy and the Green party family, created the transnational European Left Party (EL), uniting parties like the German Die Linke, Italian Rifondazione Comunista and Greek Syriza. In 2009, the EL fought the European Parliament elections on the basis of a common manifesto, emerging over the last decade as an apparently stable actor at EU level.As the first detailed study of the EL this book analyses the role of the party in European politics and the politics of the European radical left. What challenges will the EL have to overcome in order for it to become a significant force for the creation of a genuine, democratic European polity? To what degree has the EL enabled an increase in the electoral or policy influence of the radical left in Europe? Written by two of the foremost experts on the European left, this book is essential reading to those interested in how the left has fared in post-crisis Europe.