John Walsh, a professor of gerontology at USC, studies the effect of intense exercise on brain development.

FORBES: Billionaires

Our host, John Walsh, a man who'd lost his own child to terrible violence, would never let us give up on a case.

CNN: Lessons from 'America's Most Wanted': Never give up

John Walsh, a technology administrator at Deutsche Bank, managed to catch a glimpse of the delicate, dark brown winter wren after he broke away from DiCostanzo's group on a recent morning.

FORBES: Wings of Desire