It was the find of a lifetime: The bones of multiple individuals, hidden deep underground in the region of South Africa called the Cradle of Humankind. Only the slimmest expedition members could squeeze through the jagged rock channels to reach the cave and its amazing treasures. In this freewheeling tale of science and exploration, celebrated paleoanthropologists Lee Berger and John Hawks tell the story of how Berger and his team discovered rich caches of fossils representing all-new species on the human family tree. How old are these bones? How did they get so deep underground? What do they tell us about our earliest ancestors? Berger's answers transform our sense of who we are and how we got here.