One of the challenges of this section was delineating the space-time scale, as well as the historical approach. It was not possible, nor was it our goal, to eliminate the numerous time frames, topics and case studies presented. The editorial focus was the global history of Africans, emphasizing intercontinental interactions and their dynamics. However, inevitably, some regions and periods were better represented than others. Two aspects of this topic warrant particular clarification: first, the emphasis on the Atlantic was not intentional but, rather, determined by the contributions received; and second, Global Africa includes the people within the African continent itself, movements to other continents, mobility across continents and transnational identities.  
Considering that there have been different diasporic currents throughout human history, Colin Palmer (2018, pp. 215-216) divides these currents into two  
categories: the pre-modern diasporas, before 1500, and the modern diaspora, after 1500 . While the pre-modern concept is useful for distinguishing the period after the fifteenth century, the idea of a so-called 'pre-modern' Africa has Eurocentric connotations that should be avoided. For example, we consider the African diasporas from the seventh to the fourteenth century to be commercial, diplomatic and military diasporas, especially with regard to the Mediterranean and the Indian Ocean basins. Palmer divides the modern African diaspora into three currents: (1) the transatlantic slave trade, from the fifteenth to the nineteenth century; (2) the movement of African captives and free migrants to the Indian Ocean basin, East Asia and Oceania in roughly the same period; and (3) the current that began at the end of the nineteenth century has continued in the twenty-first century, and is characterized by the voluntary movement of Africans and Afrodescendants inside and outside Africa.