It's the fourth day of a scientific conference in Denver—four busy February days in a huge rabbit-warren convention center with long hallways and fluorescent lighting and serious scientists giving serious PowerPoint presentations in darkened auditoriums; four days of breakthroughs and advances—nanotech to biotech, anthropology to zoology, the whole mind-spinning stew. Four days, for the assembled journalists, of making sense of it all and banging out stories on the fly—and now comes word of what could be a light interlude: Keep an eye out for the guy carrying the head. Say what? The robotic human head. The press people for the American Association for the Advancement of Science, the conference's sponsor, say the demonstration's on for tomorrow morning.

The Man Who Mistook his Girlfriend for a Robot