By coincidence Professor Dani Rodrik has been thinking about the slave trade as well, needless to say in a more rigorous, dispassionate way than I have . . . see this post on how the countries that exported the most slaves are now the poorest in Africa, even though they were probably richer before.
On a personal note, I'm back in the USA, trying to remember the taste of fried fish with cassava greens and the warm, welcome rain of Liberia, so unlike the cold, hostile showers of Massachusetts . . . I have to confess that I have been looking at travel planning websites to see if I can afford a trip to Monrovia in December to do some more work on agriculture. The answer is probably 'no' but if anyone knows of any great fare deals between the US or London and Liberia around then, please let me know!