The question of the suppression of the slave-trade is so intimately connected with the questions as to its rise, the system of American slavery, and the whole colonial policy of the eighteenth century, that it is difficult to isolate it, and at the same time to avoid superficiality on the one hand, and unscientific narrowness of view on the other. While I could not hope entirely to overcome such a difficulty, I nevertheless trust that I have succeeded in rendering this monograph a small contribution to the scientific study of slavery and the American Negro. (Summary by W.E. Burghardt Du Bois)