This chapter introduces the theme of the volume, populism and international law, as well as its chapters. It does so by first discussing the Dutch political reality with its increasingly populist tendencies that was on the minds of the Editors when deciding to devote a volume to this theme. Subsequently, it explores briefly the many faces of populism and the different manifestations of the relationship between populism and international law. Rather than taking the so-called populist backlash against globalisation, international law and governance, at face value, this volume aims to dig deeper beyond mere ‘backlash’ rhetoric and wonders ‘what backlash are we talking about, really?’ While populism is contextual and contingent on the society in which it rises and its relationship with international law and institutions thus has differed likewise, this chapter’s historical reflections assist in our examination of what we find so dangerous about populism and problematic in its relationship with international law. It concludes by introducing the chapters individually and to some degree in relation to each other.