While neurotic robots are a staple of science fiction — just think of C-3PO in Star Wars or Marvin in the Hitchhiker's Guide to the Galaxy — they haven't really been a focus of research into how ...

Part one: The long, hard road to today. The story of Prometheus ; The First Age: language and fire ; The Second Age: agriculture and cities ; The Third Age: writing and wheels ; The Fourth Age: robots ...