This chapter introduces the book. It examines the role of policy learning in the context of European Union (EU) soft law instruments, focusing on Greece, Italy, and Spain during the critical period from the mid-2000s to late-2010s. Specifically, it explores how policy makers learn—or fail to learn—from EU initiatives like the Open Method of Coordination and the European Semester, which use non-binding governance mechanisms to foster mutual learning and harmonize member states’ social policies. In addition, it highlights the challenges posed by domestic administrative, institutional, and political structures that impede effective knowledge transfer. Using Greece as a central case study, the research reveals variations in policy learning types, including no learning, blocked learning, and political learning, and identifies the systemic constraints on these processes. By integrating the Worlds of Compliance typology, this study underscores the link between EU hard law compliance and soft law learning, offering valuable insights into enhancing policy learning for effective EU governance.