Genetics has made an enormous contribution to our understanding of human history in the last few years. The ability to trace genetic lineages through mitochondrial or Y-chromosome DNA has given us unexpected and sometimes quite astonishing insights into human history and recent human evolution. This book seeks to tell that story, at least in accessible popular form. The author, Steve Olson, is a professional writer who has worked for the US National Academy of Sciences and the Institute for Genomic Research, as well as for one of the White House’s science offices.