The Mysteries of Lightning, The Science of Sweat, Cooking with Grass

Guest host: Tracy Smith. In our cover story, David Pogue explores the mysteries and beauty of lightning. Also: Ben Mankiewicz sits down with Oscar-winning actor F. Murray Abraham; David Martin examines the alarming propensity for violent death among critics of Vladimir Putin; Dr. Jonathan LaPook profiles violin virtuoso Augustin Hadelich; Faith Salie reports on the science of sweat; and Luke Burbank talks with chefs who cook with cannabis.