This episode's headline: Taxing Issue; Agony's Cradle. The guests include JAMES C. MILLER, III, Former Reagan Adviser; FELIX ROHATYN, Investment Banker; BERYL SPRINKEL, Former Reagan Adviser; JAMES GALBRAITH, Economist; CORRESPONDENT: STEVE SMITH. Byline: In New York: ROBERT MacNeil; In Washington: JAMES LEHRER