The exceptions to this rule, however, make fundamental contributions to the understanding of world history.A particularly rich literature deals with the Atlantic slave trade and the African diaspora. Some large-scale dimensions of these topics have to do with the organization of plantation agriculture by European colonists in the Americas, the emergence of triangular trades in the Atlantic Ocean basin, the recruitment and transport of about twelve million involuntary African laborers, and the establishment of African-American societies in the western hemisphere, all of which have received considerable attention since the 1960s. Philip D. Curtin in particular has contributed to the understanding of slavery and African migration, first by placing studies of the slave trade on a solid quantitative foundation, then by understanding slavery in the context of the “plantation complex” that became such a prominent feature of the Atlantic Ocean basin during the seventeenth and eighteenth centuries.Working within this general framework, other scholars have thrown new light on developments that would be difficult or impossible to understand in the context of national communities or supposedly coherent individual societies: Patrick Manning studied the social and economic effects of slave trading in Africa as well as lands that received slave populations, for example, while John Thornton called attention to the survival of African social and cultural traditions in the Americas, and Richard Price examined the formation of maroon societies by runaway slaves.