The skull cap is thick and flat. It looks distinctively human, and yet its massive brow ridge, hanging over the eyes like a boney pair of goggles, is impossible to ignore. In 1857, an anatomist named Hermann Schaafhausen stared at the skull cap in his laboratory at the University of Bonn and tried to make sense of it. Quarry workers had found it the year before in a cave in a valley called Neander. A schoolteacher had saved the skull cap, along with a few other bones, from destruction and brought it to Schaafhausen to examine. And now Schaafhausen had to make the call. Was it human? Or was it some human-like ape?

Schaafhausen did not have much help to fall