Chapter 1 frames VSS within the transnational emergence of a regulatory space for private actors due to the difficulty for States to unilaterally regulate transboundary phenomena and the impasse at the multilateral level. Civil society organisations, producers and retailers thus emerged as regulatory actors in the domain of sustainability. Relevant characteristics of VSS are discussed in preparation for the legal analysis. The chapter also illustrates key differences between technical standards and VSS tackling, respectively, network externalities and policy externalities. Three ideal–typical categories of VSS are designed to facilitate and fine-tune the legal analysis, and to clarify the extent of public reach vis-à-vis each of three groups. The three categories of multi-stakeholder, sectoral and company schemes are established on the basis of the actors participating in standard-setting, its procedures and normative justifications behind the schemes. The chapter then illustrates the contested effectiveness of VSS, their frequent negative impact on trade and their distributional implications.