This episode's headline: Perestroika & the Poet; Summit Outlook; Moving Musician. The guests include In San Francisco: RICHARD PIPES, Harvard University; In New York: WILLIAM HYLAND, Foreign Affairs Magazine; In Boston: JOSEPH NYE, Harvard University; REPORTS FROM NEWSHOUR CORRESPONDENTS: JOANNA SIMON. Byline: In New York: CHARLAYNE HUNTER-GAULT, National Correspondent; In Washington: JIM LEHRER, Associate Editor