Slavery was brought to America by Europeans looking to make sugar. If you can get it, you need to watch this PBS show:
http://wptschedule.org/episodes/11452/Burt-Wolf-What-We-Eat/How-Sweet-It-Is-The-Story-of-Sugar/
Please remind us also to watch PBS shows on the McCarthy hearings and the Nuclear Freeze movement.
The Europeans and Americans have been pretty poor customers for slaves, as cultures go. They took it up for a brief period and then went around the world trying to abolish it. The Moslems, Orientals, and the Africans themselves have been the real enthusiasts. All those cultures that believe people are essentially ants. The American Indians kept Indian and black slaves as well.
There would have been no international African slave trade without the Arabs. It would have been confined to the incessantly warring African tribes themselves. Any book, even by a liberal historian, will make it clear that it was the Arabs alone who created and used the slave-trading routes. They bought the slaves from tribes in the interior and sold them to the rest of the world from the handful of ports that exist on the African continent. Most of the African slave trade went to the Middle East. About 5 percent went to the Americas.
It's significant that all African slavery, including America's, was supplied by Moslems.