This chapter introduces some of the main issues at stake in the distinction between the positive and the normative in economics. It first analyses the positive and the normative in the history of economic thought and shows that attempts at defining the relationship between the two have taken very different forms. By relying on this historical narrative, the chapter intends to show that using a limited number of categories to capture various ways in which the positive and the normative have been theorised often leads to overlooking major differences. It is then shown that one of the main areas of disagreement regarding more normative approaches to economics is about the exact nature and tasks of normative economics, especially regarding social evaluations and prescriptions. The final part of the chapter examines and explains the ways in which different chapters of the volume make original contributions to existing debates on the positive/normative in economics or reveal the limits of current debates and the necessity of sometimes changing the terms through which these debates are structured.