Paul Polak: Always curious, always learning

Most people retire at the age of 65. Paul Polak, however, is not most people.

The former psychiatrist — Polak holds a medical degree and was a practicing psychiatrist for 23 years — founded iDE in 1982, an international nonprofit that uses market-based solutions to address poverty. The organization claims to have lifted nearly 20 million $1-a-day, one-acre farmers out of poverty by making low-cost irrigation technology available and giving them access to markets for their crops.