Terry Gross

Daniel Lieberman is a professor in the department of human evolutionary biology at Harvard. He says that the notion of "getting exercise" — movement just for movement's sake — is a relatively new phenomenon in human history. His new book is Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding.

Trump called climate change a hoax. Biden calls it an existential threat. Washington Post journalist Juliet Eilperin talks about how Biden might reverse some of his predecessor's policies.

Sheehan, who died Jan. 7, broke the story of the Pentagon Papers and wrote A Bright Shining Lie, a Pulitzer Prize-winning book about the Vietnam War. Originally broadcast in 1988.