When I began writing this book in 1984, I imagined that I would be writing a fairly specialized work for scholars and a few interested laypeople, as a way of advancing Africa into the Braudelian scheme of Atlantic history that inspired me. In my vision, it was to be a reference book for the non-Africanist historian and would be based on a virtually complete reading of the primary sources. To that aim, it was originally to offer coverage up to about 1650 (the limit within which I felt I could handle the sources comprehensively) and would be mostly confined to Africa, my area of expertise. In fact, the first draft of the book had only one rather sketchy chapter on the American side of the exchange.

I was gradually persuaded that the book would be more useful if it were more ambitious, and as it grew into the volume published in 1992, I added a much larger and more carefully argued section on the Americas in place of the original chapter. I also expanded the time frame to 1680, mostly so that I could have a few meaningful things to say about early colonial North America.

As I expanded the territorial and temporal boundaries of the book, I also slowly and reluctantly recognized that I could never deal with the primary sources comprehensively, especially for the American side of the ocean.