This is a good book by Nick Wade which covers human prehistory as seen mostly from the study of genetics.
It is a book about magic and magical it is. Quite long but fun to read, Susanna Clarke has come up with a winner for her first novel, Jonathan Strange and Mr Norrell.
The First Human is a good and readable book about the search for the oldest hominin fossils. It describes the science, the fieldwork as well as the disputes in the field of paleoanthropology.