David Fieldhouse suggested this book. In writing it, I have strayed far from my expertise as a documentary historian. John Sutton is partly to blame for that because he first interested me in African prehistory through his lectures at Dar es Salaam. David Phillipson kindly read and commented on my typescript, as did John Lonsdale, who has taught me so much. John Alexander and Timothy Insoll helped with books. To the first edition, published in 1995, I have added a chapter, current to 2006, and I have extensively revised the chapters on prehistory and the Atlantic slave trade, together with less substantial revisions to take account of recent scholarship on other periods. The mistakes that remain are my own.