Like many books that were originally dissertations this one has gone through numerous revisions since it was presented to Cambridge University in 1969. In that year, a considerable body of literature appeared on the subject of ethnicity and, since then, a number of important works on several issues relating to migration and trade in West Africa, the Asante, and the Mossi have been published. Over the last five years, partly as a result of these publications, my views on a number of issues raised in this book have changed, and indeed are still changing. But there comes a point at which one has to accept the somewhat patchwork quality of one's endeavor and the knowledge that interpretations inevitably change as one's awareness of facts and their implications grows.

My debts in writing this book are many and go back for such a long time that it is possible to mention only the most important ones. First, I want to acknowledge my enormous gratitude to the people in Ghana and Upper Volta whose lives I have tried to understand. In the text, all names have been changed, except those of persons whose positions as public officials are so well known as to make this caution meaningless. There are points in a book such as this when one is uncertain whether one is writing anthropology or history, or indeed if that is a meaningful distinction at all. At these moments the decision as to whether or not to change names becomes difficult.