Adding to a heap of impressive recent books about old bones, “The Skull in the Rock” provides a dual picture of science being practiced in all its current high-tech glory and of life as it was precariously lived by our hominid ancestors about 2 million years ago. The link between the two is Lee R. Berger, who grew up in small-town Georgia and became a paleoanthropologist based in South Africa. The book, co-written with Marc Aronson, begins in August 2008, near Johannesburg, as Berger and his 9-year-old son, Matthew, explore a protected area that had yielded many important fossils. Matthew’s remarkable discovery that morning led to the identification of a new species, Australopithecus sediba, whose traits combined the archaic with the modern, the ape and the human. In chapters well-illustrated with photographs of the project’s groundwork and labwork, as well as fascinating reconstructions of some long-gone individuals, “The Skull in the Rock” explains where this skeleton, nicknamed Karabo, probably stands in the evolution from primates to humans. The authors note that some scientists disagree with Berger’s conclusions, but they argue convincingly that the key thing about finding Karabo is that it clears the way for the next discovery.