This article forms part of a six-part Series on trade and health, and sets the stage for this Series by analysing key aspects of the relationship between trade and health. The Series takes stock of this relation and provides timely analysis of the key challenges facing efforts to achieve an appropriate balance between trade and health across a diverse range of issues. This introductory article reviews how trade and health have risen and expanded on global policy agendas in the past decade in unprecedented ways, describes how trade and health issues are respectively governed in international relations, examines the ongoing search for policy coherence between the two policy spheres, and highlights the topics of the remaining articles in the Series.