Marcia Franklin talks with historian Tiya Miles about her book, “All That She Carried,” which won the National Book Award. It tells the story of “Ashley’s sack,” a bag given to an enslaved girl by her mother in the 1850s. The two discuss how a material object can bring untold history alive, and also talk about Miles’ book, “Night Flyer,” which looks at the effect of the outdoors on Harriet Tubman.