Feeling bored with the old routine? You might consider jumping off the nearest skyscraper. And if that starts to feel humdrum, get that extra thrill by doing it upside down. On the Edge: the Nature of Risk leaps into the peculiar world of people who need a regular "risk fix". "I need it to feel balanced," chirps Marta Empinotti, as she prepares to throw herself headfirst from a bridge. Meet Marta and other extreme sports enthusiasts such as Stephen Lyng, whose passion for fast motorcycles nearly cost him his life. And Tom Budd, deal-maker and risk-taker in the world of investment banking, who gets an adrenalin rush from racing cars and hunting grizzly bears. Is there something about security-conscious societies that produces this taste for hair-rising adventure? Can genetic factors help explain the phenomenon? Interviews with Dr. Dean Hamer and Professor Marvin Zuckerman illuminate the culture and science of risk, helping to explain why some people feel fully alive only when courting death.