“The music is at the core of what it means to be an American,” says Bruce Springsteen of the work of folk-music icon Woody Guthrie (1912-67), who is recalled via archival footage, photos and recordings. Included in this thoughtful profile are his 1930s contact with Dust Bowl refugees, inspiring many of his most memorable songs; and his battle with Huntington's disease. Included: insights from his sister, Mary Jo Guthrie Edgmon; daughter Nora Guthrie; Pete Seeger; and biographer Joe Klein.