Mr Olson's book starts out extremely well, but sags after a few chapters. The initial segments on mitonchondrial DNA and our genetics is probably the most readable and understandable treatment that I have seen. About halfway through the book, however, Olson stops trying to trace human migration and development. His emphasis becomes avoiding rascism. At this point, the history and science dwindles away and the emphasis becomes how intermixed our gene pools are. It was almost as if his underlying motivation was a desire to use science to prove a political position. It became rather pedantic at this point. I was very disappointed after the strong start that the book made.