What is a human life worth?

A few years ago, when he was in his mid-40s, Zell Kravinsky gave almost all of his $45 million real estate fortune to health-related charities, retaining only his modest family home in Jenkintown, near Philadelphia, and enough to meet his family’s ordinary expenses. After learning that thousands of people with failing kidneys die each year while waiting for a transplant, he contacted a Philadelphia hospital and donated one of his kidneys to a complete stranger.

What Should a Billionaire Give – and What Should You?