When was the last time something left you in awe? Maybe it was staring at the millions of stars in a vast night sky or marveling at the birth of a child. Dr. Dacher Keltner, the founding director of the Greater Good Science Center at the University of California, Berkeley, has spent years studying the biological and evolutionary origins of human emotion. His latest book, "Awe: The New Science of Everyday Wonder and How It Can Transform Your Life," presents a radical investigation and deeply personal inquiry into the elusive emotion of awe. In this week's episode he talks with host Dr. Alan Campbell about how a season of profound grief led the scientist to re-evaluate some of his long-held ideas about life and death, the areas in which he experiences awe the most, and the ways scientists have found to study and measure a concept as elusive and complex as awe.