Whatever the sector-codification and management of legal norms, climate change regime, governance and multilateralism, social-ecological interactions, health, natural resource managementlaw and public policies form complex systems resulting from the diversity of agents, resources, norms and principles they imply, and from the multiplicity of processes and activities that contribute to the evolution of the state of affairs. The complexity is also demonstrated by the poor control that stakeholders and decision-makers have over the impacts of the instruments deployed and over the responses to their implementation. In such a context, as evidenced by the studies gathered in this volume, the methods deployed to interpret, understand or explain the law or the public policies in action multiply the types of approaches and the means solicited for their study. However, an emerging trend not only provides analytical tools, but also inspires several approaches to phenomena related to law and public policy. It consists in apprehending these phenomena in terms of various networks, supports for change, intricate exchanges, knowledge and innovation, management, but besides essential ingredients of the incessant, sometimes labile, interactions between the systemic components.