This episode's headline: The Future. The guests include TIM ONOSKO, ""Future"" Historian; ISAAC ASIMOV, Science Fiction Writer; DICK TERESI, Omni Magazine. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor; LEWIS SILVERMAN, KENNETH WITTY, Producers; MAURA LERNER, Reporter