The willingness of Africans to participate in the slave trade in Africa allowed it to flourish. Africans delivered fellow Africans into the clutches of European subjugation and servitude, something the mosquito made impossible for Europeans to do themselves. The mosquito would not allow Europeans to pluck Africans from their homelands. Without African slavery, New World mercantilist plantation economics would have failed, quinine would not have been discovered, and Africa would have remained African. The entire Columbian Exchange would have been vastly different, or perhaps not have occurred at all.
As it was, however, the Portuguese, and eventually the Spanish, English, French, Dutch, and other Europeans, were able to tap into the existing internal African slave culture that revolved around captives of war. Africans initially sold their captives to the Portuguese, and small, localized slave trade emerged. Originally, it generally operated under the cultural umbrella of customary and conventional African slavery. By exploiting this traditional feuding among African nations and social networks, Europeans were able to introduce a vastly different form of captive slavery, one of bulk commercial export. African leaders and monarchs began raiding traditional enemies and allies alike, solely for the purpose of capturing slaves to sell at a growing number of slave forts on the coast, operated by an increasingly broad range of European nationalities. The European demand was met by an African supply of African slaves.

The trade in human beings from Africa was a response to externa factors. At first, the labor was needed in Portugal, Spain, and in Atlantic islands such as , , and the Canaries; then came the period when the and the Spanish-American mainland needed replacements for the Indians who were victims of genocide; and then the demands of Caribbean and mainland plantation societies had to be met. The records show direct connections between levels of exports from Africa and European demand for slave labor in some part of the American . When the Dutch took in Brazil in 1634, the director of the Dutch West Indian Company immediately informed their agents on the Gold Coast that they were to take the necessary steps to pursue the trade in slaves on the adjacent coast east of the Volta—thus creating for that area the infamous name of the “Slave Coast.” When the British West Indian islands took to growing sugar cane, Gambia was one of the first places to respond. Examples of this kind of external control can be cited right up to the end of the trade, and this embraces also, since European markets in the islands became important in the eighteenth and nineteenth centuries, and since demand in places like Brazil caused Mozambicans to be shipped around the .

In speaking of the European slave trade, mention must be made of the U.S.A., not only because its dominant population was European but also because Europe transferred its capitalist institutions more completely to North America than to any other part of the globe, and established a powerful form of capitalism—after eliminating the indigenous inhabitants and exploiting the labor of millions of Africans.

European planters and miners enslaved Africans for economic reasons, so that their labor power could be exploited. Indeed, it would have been impossible to open up the and to use it as a constant generator of wealth, had it not been for African labor. There were no other alternatives: the American (Indian) population was virtually wiped out and Europe’s population was too small for settlement overseas at that time. Then, having become utterly dependent on African labor, Europeans at home and abroad found it necessary to rationalize that exploitation in racist terms as well. Oppression follows logically from exploitation, so as to guarantee the latter. Oppression of African people on purely racial grounds accompanied, strengthened, and became indistinguishable from oppression for economic reasons.

It is not the state of slavery so much as the process of enslavement that is intolerable: and it is worth noting that the European slave trade was principally for the transport of people already enslaved. That is to say, the traders purchased captives from the warrior tribes. Undoubtedly the trade stimulated the raiding, but free blacks first captured other free blacks and then sold them to the whites.

The first four centuries of Afro-European trade in a very real sense represent the roots of African underdevelopment. Colonialism flourished rapidly from a European viewpoint, because several of its features were already rooted in Africa in the preceding period. One of the most decisive features of the colonial system was the presence of Africans serving as economic, political, and cultural agents of the European colonialists. Those agents, or “s,” were already serving European interests in the pre-colonial period. The impact of trade with Europe had reduced many African rulers to the status of middlemen for European trade; it had raised ordinary Africans to that same middleman commercial role; and it had created a new trading group of mixed blood—the children of European or Arab fathers. Those types can all be referred to as “compradors,” and they played a key role in extending European activity from the coast into the hinterland, as soon as Europeans thought of taking over political power.

On the whole, the process by which captives were obtained on African soil was not trade at all. It was through warfare, trickery, banditry, and kidnapping. When one tries to measure the effect of European slave trading on the African continent, it is essential to realize that one is measuring the effect of social violence rather than trade in any normal sense of the word. Many things remain uncertain about the slave trade and its consequences for Africa, but the general picture of destructiveness is clear, and that destructiveness can be shown to be the logical consequence of the manner of recruitment of captives in Africa.

African rulers found European goods sufficiently desirable to hand over captives which they had taken in warfare. Soon, war began to be fought between one community and another for the sole purpose of getting prisoners for sale to Europeans, and even inside a given community a ruler might be tempted to exploit his own subjects and capture them for sale. A chain reaction was started by European demand for slaves (and only slaves) and by their offer of consumer goods—this process being connected with divisions within African society.

For most European capitalist states, the enslavement of Africans had served its purpose by the middle of the nineteenth century; but for those Africans who dealt in captives the abrupt termination of the trade at any given point was a crisis of the greatest magnitude. In many areas, major social changes had taken place to bring the particular regions effectively into the service of the European slave trade—one of the most significant being the rise of “domestic slavery” and various forms of class and caste subjugation. African rulers and traders who found their social existence threatened by the earliest legal edicts such as the 1807 British act against the trade in slaves found ways of making contact with Europeans who still wanted slaves.

Incidentally, it was Europeans living in Europe who wanted to abolish the slave trade. They wanted to end it all over the world. So also ín Africa and also in the Middle East. It was just important to come up with arguments to justify such an abolition. One of the arguments devised at the time was that our slave trade threatened to deform entire countries. But that argument, as it now turns out, is historically incorrect. If you look at the quantities and the fact that slavery existed long before the Europeans appeared on the coast there, and that it continued even after the Europeans stopped doing it, I see no scientific arguments at present to attribute primary responsibility to the slave trade for Africa's current economic position in the world.

For centuries, Europeans dominated the African continent. The white man arrogated to himself the right to rule and to be obeyed by the non-white; his mission, he claimed, was to "civilize" Africa. Under this cloak, the Europeans robbed the continent of vast riches and inflicted unimaginable suffering on the African people.

When the Portuguese and the Spanish were still in command of a major sector of world trade in the first half of the seventeenth century, they engaged in buying cotton cloth in India to exchange for slaves in Africa to mine gold in Central and South America. Part of the gold in the Americas would then be used to purchase spices and silks from the Far East. The concept of metropole and dependency automatically came into existence when parts of Africa were caught up in the web of international commerce. On the one hand, there were the European countries who decided on the role to be played by the African economy; and on the other hand, Africa formed an extension to the European capitalist market. As far as foreign trade was concerned, Africa was dependent on what Europeans were prepared to buy and sell.

By 1885, when European kings, princes and presidents sat in Berlin to slice up the African continent with their geometrical instruments, the African people had already been devastated by the ravages of the West Atlantic slave trade. In West and Central Africa, the indigenous civilisations lay in ruins, from the sophisticated Saharan trade routes with at their centre, to the empires of . On the Eastern seaboard, the European invasion, led by the Portuguese, defeated and destroyed the city states of Swahili civilisation. All in all, some 40,000,000 souls are estimated to have perished in the triangular slave trade, which lasted for roughly four centuries, 1450–1850. The development of the European and North American industrial revolution and the global lead this gave to Europe and America was in no small measure built on the back of Africans. The colonial episode was thus the tail end of long and destructive contact between Europe and Africa. The slave trade tore apart the very social fabric of African societies, destroying their internal processes of change. It imposed on the continent a European worldview in which the peoples of Africa were at the lowest rung of the so-called civilised order. No other continent, including those that suffered formal European colonisation, had their social, cultural and moral order destroyed on this scale.

Slaving gave rise to a division of labor in which the business of capture, maintenance, and overland transport of slaves was in African hands, while Europeans took charge of transoceanic transport, the "seasoning" or breaking in of slaves, and their eventual distribution.