Africa is commonly marginalized in global social studies, whether of present or past. This essay makes the case for the substantial importance of Africa through a systematic comparison with Eurasia. It documents the large area and the relatively dense population of Africa, in past and present, as compared with Eurasia and also with the Americas. The essay gives particular attention both to sub-Saharan Africa and to the long Afro-Eurasian borderland from Gibraltar to the Bab al-Mandab, and briefly explores the interactions of Africa, Eurasia, and their borderland since the beginnings of humanity. In the course of the comparison, the essay raises the question of whether the theory and methodology of historical globalization studies need to be more fully specified in order to ensure inclusion of the African region and perhaps other historical situations that have been insufficiently represented in the understanding of globalization.