Dr. Robert Butler, 81, says he felt a need to "sum up" all he has learned in 50 years of studying longevity.

"This was a hard book to write," he says of his massive tome, "The Longevity Revolution" (Public Affairs, 2008). 'There is a paradox. On one hand, longevity is a great human achievement, and on the other are the gloomy people who think we can't afford old age."

Q. This is a very dense book. It is simply full of thought-provoking concepts on scientific knowledge about longevity, the cost of longevity, the motivation to work.

A. I realize you are right. It is a dense, tough book. It requires thinking, and I hope it will stimulate conversations on the myths, misunderstandings, gloom around longevity. You know, this is a great human achievement, adding years to our lives.   Read More...