To cynics, the upgraded-self movement—aka body hacking—can seem a reckless and narcissistic pursuit. After all, treating your body like a home science kit can have serious consequences (scarring, bleeding, pain on the scale of passing out). Yet tinkering with human hardware is a centuries-old pursuit. Bolting titanium plates onto problem spines has become downright common. Today's transhumanists take it further. They seek to extend the senses and co-mingle them, allowing themselves to do things like detect Wi-Fi, hear colors, sense magnetic north, and see in the dark. Technology is driving the trend. But so are a few renegade surgeons—operating in an ethical gray area—and a growing number of innovative grinders, all of them hoping to one day push the cyborg off the Comic-Con floor and out onto Main Street.