I recently read Ancestral Journeys: The Peopling of Europe from the First Venturers to the Vikings by Jean Manco. You can find more information at her website, but I pretty much would recommend this book to all my non-scientist readers. I'd recommend it to many of the scientists too, if you are rather weak on archaeology, because that's where Manco's knowledge is really impressive. It's not a perfect book, and I don't agree with all the details, but it's a very detailed, dense, and fast read. There was a question below in regards to the Fast Company profile of 23andMe and what they're trying to do. A major ethical issue brought up is whether it is acceptable to type children and disclose possible disease risk later on in life. As an extreme case, what if you find out that your child is going to develop a life threatening disease by the time they're 40? My own perspective as a parent is that I'd like to know, and I'd probably want to tell my child as soon as I think they can handle it. The reason is simple: you base your life decisions on various aspects of life expectancy. People put things off, or forgo consumption, all the time.