What is commercial agriculture? For present purposes two types come to mind: one that produces for local markets (where the output is sold within say 50 km of the point of production) and the other that is able to supply markets further afield. We can assume that before low-cost sea or inland waterway transportation developed, the populations of large cities everywhere survived on the basis of local commercial agriculture. In that sense, commercial agriculture in Africa, as in the rest of the world, must go back almost to the point where human beings began to draw most of their sustenance from agriculture as opposed to hunting and gathering. But the thrust of the present collection is, I believe, on commercial output for faraway markets. For this we have to start with the recognition that distance and lack of transportation infrastructure were the major barriers to trade in produce almost everywhere around the globe until quite recently.

As a consequence agriculture that produced food, drink and the raw material for clothing (including dyes) that could be traded over long distances was quite rare before the early modern era and where it existed it contributed little to the basic food, clothing and shelter requirements of either the sellers of the produce or its buyers. Kola nuts and spices, to take two random examples, were not central to the well-being of consumers nor did they provide a livelihood for many producers.