Where did modern humans come from and how important are the biological differences among us? Are we descended from Neandertals? How should we understand the connections between genetic ancestry, race, and identity? Were Native Americans the first to inhabit the Americas? Can we see evidence of the Viking invasions of Ireland a millennium ago even in the Irish of today? Through engaging examination of issues such as these, and using non-technical language, shows how anthropologists use genetic information to suggest answers to fundamental questions about human history. By looking at genetic variation in the world today and in the past, we can reconstruct the recent and remote events and processes that have created the variation we see, providing a fascinating reflection of our genetic past.