You may know him simply as the inventor of the soon-to-be-mass-marketed Segway transporter (a.k.a. "Ginger," a.k.a. "IT"), but Dean Kamen has a history of invention stretching back to his days as a teenager devising mechanical gadgets in his parents' basement. In 1982 Kamen purchased an abandoned textile mill by the banks of New Hampshire's Merrimack River, and he has invested more than $10 million to transform the red brick buildings into the ultimate inventor's playground. His company, Deka Research and Development, now holds more than 200 patents, many of them on innovative health-care devices, such as a portable insulin pump, a compact dialysis machine and a stair-climbing wheelchair called the iBOT. On a recent afternoon, Kamen led Technology Review contributing writer Evan I. Schwartz on a whirlwind tour of the 13,500-square-meter facility, showing off everything from Deka's cavernous machine shop to the nearby Segway spinoff's design and test center, where engineers are fashioning future improvements for the self-balancing, battery-powered transporter. This is where Kamen and 300 employees engage in what they describe as a mysterious and messy process, one in which failure is far more common than success, and no one knows what the final product will look like.