The Atlantic slave trade is well documented, but I'm trying to find more information regarding the nature of slavery BEFORE the Europeans began participating in it extensively. It seems like there are a lot of conflicting viewpoints from various historians regarding the extent to which contact with Europeans was driving the slave trade, or if the European slave trade market served as an outlet for trade that was already going on.
As a follow up to that, to what extent were West Africans willing participants in the slave trade with European partners? Or was it more of a case of domination of the Europeans that led to the burgeoning slave trade, rather than a mutually beneficial economic relationship?
Slave trading was already going on in West Africa by the time Portuguese Explorers began going on slave raids into the Senegambia coast in 1444. Keep in mind the "slave trade" we think of today, with a well assigned system, rules and way of treating slaves already in place. Slaves where gained by raids and through war, to which they where often put out to work, though treated much better than the Europeans did, most slaves where used as servants and used for manual labor, though given much better nourishment and treatment.
Many slaves would be treated as part of the family once enslaved, and would be allowed to eat and stay in the house of whoever family they where with. Slaves would be traded though, usually to lend off their talents or to just gain money.
When the Portuguese arrived in 1444 they sent out slave raids on the Senegambia coast, somewhat successfully until West African (Mali) forces began naval scrimmages against the portuguese vessels, often using much lower quality boats, yet, due to their skill with poison arrows where able to put the Portuguese in an increasingly tough situation until in 1456 they send Courtier Diogo Gomes to establish peace between Portugal and the Senegambia coast ruling Mali Empire (though the empire was in its decline, soon to transform into the Songhai empire)
in 1462, after peace was established, Portugal shifted its focus from raids and battles to trade with the Africans. Still desiring the original recourse they came for, slaves, they heightened demand greatly. The West Africans, seeking the valuable European goods began heightening their slave trade, taking slaves from rival nations and villages to be sold to the Europeans.
The Africans (those not being enslaved) and Europeans both prospered off of this, West Africans became wealthy off of the trade of rival nations and slave trade blossomed as a great new economic tool was established.
In short, the modern thought that Africans where "Enslaving their own" is incorrect. Slaves came from enemy and warring clans and nations, as separate culturally and individually as, say, Vietnam and China. This meant west african nations could now profit from war and battle with their rivals, and that they did. They where quite willing to trade with European partners due to the great goods the Europeans offered, and they traded slaves by their own free will. It was like any other business in a sense. Slaves already owned where traded to Europeans and more where captured after that. It was a mutually beneficial economic relationship, though it damaged the relations in west Africa greatly, throwing the nations into a time of constant tension.
Sources:
[The Royal Kingdoms of Ghana, Mali and Songhay: Life in Medieval Africa | by Patricia McKissack and Fredrick McKissack] (http://www.amazon.com/Royal-Kingdoms-Ghana-Mali-Songhay/dp/0805042598/ref=sr_1_1?s=books&ie=UTF8&qid=1414292037&sr=1-1&keywords=Mali+%28Empire%29)