This volume explores an understudied aspect of courts: The extent to which informal institutions and relational networks (e.g., professional, clientelist, family etc.) relations affect how courts are organised and operate. For instance, to what extent can ‘good personal relations’ outweigh professional merits in judicial appointment processes? Or in what ways do international or domestic judicial networks help protect courts against other branches of power? Our relational-institutional perspective allows us to better understand a variety of important processes for the comparative study of courts – including judicial appointments, judicial decision-making, judicial administration, institutional development, inter-branch relations, corruption, and court reform, among others. More importantly, an emphasis on informality sheds new light on the accountability role of courts in democratic regimes, at a time when democracy worldwide is at risk and authoritarian regimes are on the rise. Bringing together the thoughts of scholars with different levels of seniority and disciplinary expertise, this volume offers cross-national engagement with theory, providing systematic analyses of the configuration, operation, and roles of informal institutions and relations, and their importance in different socio-political contexts and legal systems.