This introduction to the volume starts with some reflections on the (im)possibility and politics related to clearly defining soft law in the field of human rights. It proceeds with looking into academic literature on the role of soft law in international relations and then sets out a more practice-oriented, bottom-up approach to examining soft law across different fields. The introduction assumes that soft law fulfils at least two main functions in international human rights: it can be norm-filling and norm-creating. The introduction analyses briefly these two main functions of soft law. On this basis a tentative framework for analysing the roles of soft law in emerging and established human rights regimes is set forth. The final section outlines the structure of the volume and the individual contributions.