A.J. Jacobs is a journalist and author of four New York Times bestsellers. His books include “The Year of Living Biblically,” “Drop Dead Healthy” and “The Know-It-All.” His most recent book is “Thanks a Thousand: A Gratitude Journey.” He is a contributor to NPR, Esquire and The New York Times, among others. He has also given several TED talks. He used to have a voluminous beard.