 Blackstone Publishing presents Who We Are and How We Got Here, Ancient DNA, and the New Science of the Human Past by David Reich. This book is read by John Muscoe for Seth and Leah. Introduction This book is inspired by a visionary, Luca Cavalli-Sorza, the founder of genetic studies of our past. I was trained by one of his students. And so it is that I am part of his school, inspired by his vision of the genome as a prism for understanding the history of our species. The High Watermark of Cavalli-Sorza's career came in 1994, when he published The History and Geography of Human Genes, which synthesized what was then known from archaeology, linguistics, history, and genetics to tell a grand story about how the world's peoples got to be the way they are today. The book offered an overview of the deep past. But it was based on what was known at the time, and was therefore handicapped by the paucity of genetic data then available, which were so limited as to be nearly useless compared to the far more extensive information from archaeology and linguistics. The genetic data of the time could sometimes reveal patterns consistent with what was already known. But the information they provided were not rich enough to demonstrate anything truly new. In fact, the few major new claims that Cavalli-Sorza did make have essentially all been proven wrong. Two decades ago, everyone from Cavalli-Sorza to beginning graduate students such as myself was working in the dark ages of DNA. Cavalli-Sorza made a grand bet in 1960 that would drive his entire career. He bet that it would be possible to reconstruct the great migrations of the past based entirely on the genetic differences among present-day peoples. Through study after study over the subsequent five decades, Cavalli-Sorza seemed to be well on the path to making good on his bet. When he started his work, the technology for studying human variation was so poor that the only possibility was to measure proteins in the blood using variations like the A, B and O blood types that are tested by physicians to match blood donors to recipients. By the 1990s, he and his colleagues had assembled data from more than 100 such variations in diverse populations. Using these data, they were able to reliably cluster individuals by continent based on how often they matched each other at these variations. For example, Europeans have a high rate of matching two other Europeans, East Asians to East Asians and... Sample complete. Ready to continue?