This episode's headline: Progess to Peace; Talking Drugs. The guests include YASSER ARAFAT, Chairman, PLO; YITZHAK SHAMIR, Prime Minister, Israel; KING HUSSEIN, Jordan; DENNIS ROSS, State Department; WILLIAM QUANDT, Brookings Institutions; EHUD YAARI, Journalist; RASHID KHALIDI, University of Chicago; RICHARD GREGORIE, Former Federal Prosecutor. Byline: In Washington: JAMES LEHRER; In New York: CHARLAYNE HUNTER- GAULT