Edward W. Said was a professor and literary critic at Columbia University who was the most prominent advocate in the United States of the cause of Palestinian independence. Dr. Said was born in Jerusalem during the British Mandate in Palestine and immigrated to the United States when he was a teenager. He spent a long and productive career as a professor of comparative literature at Columbia and wrote several widely discussed books, among them ''Orientalism'' and ''Culture and Imperialism.'' He was an exemplar of American multiculturalism, at home both in Arabic and English, but, as he once put it, ''a man who lived two quite separate lives,'' one as an American university professor, the other as a fierce critic of American and Israeli policies and an equally fierce proponent of the Palestinian cause. Though a defender of Islamic civilization, Dr. Said (pronounced sah-EED) was an Episcopalian married to a Quaker. He was also an excellent pianist who for several years wrote music criticism for The Nation. From 1977 to 1991 he was an unaffiliated member of the Palestine National Council, a parliament in exile. Most of the council's members belong to one of the main Palestinian organizations, most importantly to Yasir Arafat's Palestine Liberation Organization, but some belonged to smaller organizations believed responsible for terrorist operations against Israelis and Americans, such as George Habash's Popular Front for the Liberation of Palestine.