In today’s increasingly complex and interdependent world, the role of parliaments remains a relatively understudied research topic. The multiple patterns of global governance are mostly dominated by the executive branches of government, with parliaments remaining on the sidelines. Anne-Marie Slaughter in her work A New World Order (2004) described the global order as a network of transgovernmental network relations. At the same time, she noted the role of parliaments in networked globalism. Her analysis concluded that parliaments lack the ability and interest to network with other parliaments in the world, and essentially run behind the advanced governmental interplays that effectively shape global governance. Through the prism of current research on parliamentary cooperation in the European Union (EU), the present volume aims to revisit Slaughter’s perspective (see also Janeia 2015). At the same time, this volume obviously adds to the literature of European foreign policy, which so far has treated parliamentary activity and relations in the EU’s external relations rather as an afterthought. Only lately has attention shifted towards an increased role of the European Parliament (EP) and national parliaments, especially with regard to international agreements and trade policy (Rippoll Servent 2014; Rosen and Raube 2018; Wouters and Raube 2018; Woolcock 2012). Research on parliamentary cooperation shows the increasing networking of parliaments not only in the EU (Crum and Fossum 2009; Lupo and Fassone 2016) but also between the EU and actors outside the EU (see Costa and Dri 2014; Jan_i_ and Stavridis 2016). This volume also focuses on comparative examples of parliamentary cooperation of actors and organizations outside the EU. Overall, it not only sheds light on EU parliamentary cooperation, but also on the scope and role of parliamentary networks in an increasingly interdependent world. As such it aims to make a contribution to both the global governance and EU external relations discourses by highlighting the role of parliaments.