This chapter introduces the distinction between source, transit, and demand as geographical and jurisdictional phases of the overall global antiquities trafficking system. It explores the roles and routines at each stage: of looters, traffickers, receivers, and collectors, as well as dealers, brokers, and facilitators. It reviews the evidence on why people loot, and the contextual circumstances in which countries and regions become more likely to be afflicted by looting. The transit phase is introduced as an interface between the criminal looting activity at source and the insertion of cultural objects into the legitimate public supply chains of the antiquities market in destination countries. In this way, transit is suggested to be a ‘transformation process’. At the destination market, the role of collectors, museums, auction houses, and other actors is considered.