When we first sat down, I asked Kamen a simple question: How did you get interested in the water crisis? The answer turned into a highlights tour of his career, before he became famous or wealthy. Kamen is a natural storyteller, and his narrative unspools at high speed. Now 63, he grew up in Long Island, New York, and he ended up leaving college to start his first company, AutoSyringe, in 1976, to address a problem he’d heard about from his brother, a medical student: Certain patients needed such frequent treatment that trips to the hospital prevented them from living productive lives. Kamen’s solution was the world’s first wearable infusion pump, which administered doses of medication automatically. It was a hit, and Kamen sold AutoSyringe to Baxter International, a health-care company. He was just 30 years old.