When there are more significant researchers than significant specimens, and the question is what has made us human, the scholarly knives are sharper than knapped flints. Palaeoanthropology is a highly strung discipline in which strength of conviction makes up for a shortage of raw material and cherished hypotheses are constantly vulnerable to unexpected new discoveries. It makes an exciting spectator sport, notwithstanding the frustrating tendency of factions to draw opposite conclusions from the same weathered fragments of ancient bone.

Chris Stringer, the leader of human origins research at the Natural History Museum, occupies a fascinating position in the volatile study of our own natural history. Over forty years he has become a world authority, the go-to expert without a quote from whom no media report on new