Mention slavery to most Americans and they reflect on the sad experience in U.S. history. Most were never taught that slavery was until very recently a universal insititution. And most slaves that made it from Africa to the western hemispehere were first enslaved by other Africans. This is why it is a good thing that Henry Louis Gates sets the record straight in this NY Times op-ed.
Not all of history is mainstream history and not all mainstream history gets taught in the schools. With any luck, mention slavery to a school kid some years from now and her or she will reflect on a very sad but universal part of human history. Moral progress, where we find it, must be acknowledged and celebrated.