What happens when an engineer loses his legs in a mountain-climbing accident? In the case of Hugh Herr, he uses his brilliant mind to overcome his physical disability—and the result is a set of prosthetic legs like none ever seen before. Now Herr climbs at a more advanced level than he had before the accident—both literally and figuratively: His achievements have led him to the brink of discoveries on the future of human-computer interaction. Will we all be cyborgs one day? Hugh Herr says he has the answer.