They gather in remote valleys and mountain strongholds, and only a handful of initiates are permitted to know their mystic rites or to read their "Six Books of Wisdom." Their faith is a baffling hybrid of Greek philosophy and Muslim mysticism; they revere Jesus, Moses and Muhammad equally. Though their sect is technically an offshoot of the Isma'ili Muslim sect, it shares ideas with Chinese and Indian religions. Such are the shadowy outlines of the mysterious Druze, a self-enclosed feudal group famous for its autonomy and military prowess. Of Lebanon's dozen or more sects, the Druze are said to be the fourth largest, with a membership of 250,000 (there are roughly 260,000 in Syria, as well as some 40,000 in Israel). Yet the Druze's solidarity and fierce sense of loyalty have given them clout disproportionate to their numbers. Ever since 1975 the leader of the Druze has served as the head of the Lebanese left.