As medicine and public health make it possible for us to stay healthy well into our eighties, nineties, and beyond, we are challenged to find purpose in the gift of those extra years. Marc Freedman, president and CEO of Encore.org, believes that dedicating ourselves to the greater good is the pathway to fulfillment. In his new book, How to Live Forever, he reflects on the value of knitting the generations together, warns against the perils of age segregation, and issues a stirring cry for older people to help younger ones thrive.