Dr. Stuart Brown came to research play through research on murderers -- unlikely as that seems -- after he found a stunning common thread in killers' stories: lack of play in childhood. Since then, he's interviewed thousands of people to catalog their relationships with play, noting a strong correlation between success and playful activity. His book Play describes the impact play can have on one's life.

With the support of the National Geographic Society and Jane Goodall, he has observed animal play in the wild, where he first concieved of play as an evolved behavior important for the well being -- and survival -- of animals, especially those of higher intelligence. Now, through his organization, the National Institute for Play, he hopes to expand the study of human play into a vital science -- and help people everywhere enjoy and participate in play throughout life.