This handbook provides an introduction to Voluntary Sustainability Standards as instruments to make international trade more sustainable. Chapter 1 sets out to describe what VSS are, how they have emerged and how they have evolved. Chapter 2 delves deeper into how VSS work to achieve sustainability goals. Chapter 3 takes stock of the current literature and evidence on the effectiveness of VSS. Chapter 4 turns attention to the use of VSS by other trade-related policy instruments.