Bruce Nauman, Maya Lin, Louise Bourgeois and Kerry James Marshall, "four contemporary artists who deal in notions of identity," says Steve Martin, who introduces the hour. Marshall uses black themes in his paintings and installations; 90-year-old Bourgeois, a sculptor, frequently fashions hands; Lin, known for the Vietnam War Memorial, is seen at work in Grand Rapids, Mich. And Nauman makes psychologically infused videos and installations, including an outdoor stairway.