Sarah Jessica Parker fills in again for Leonard Lopate. World-famous ballet dancer Gelsey Kirkland and her husband, Michael Chernov, talk about the history of classical ballet and about launching the Gelsey Kirkland Conservatory of Classical Ballet. Ashley Bouder and Sara Mearns tell us what it’s like to be principal dancers with the New York City Ballet. Anthony Marra discusses his debut novel, A Constellation of Vital Phenomena. And Glenn Lowry, director of the Museum of Modern Art, describes what goes into MoMA’s major shows and talks about the future of museums.