Islam, the youngest of the world's major religions, is today its fastest-growing faith - over 1.2 billion people follow the teachings of the Koran. But many Americans know little about this religion and its followers. Islam shares much in common with the other great Western faiths. Muslims believe in the same God as Christians and Jews. The Koran describes Jesus as a great prophet, and includes more references to the Virgin Mary than does the New Testament. The word "Islam" is derived from a word that means "peace" and for centuries, Islam ruled as the greatest, most tolerant, and most diverse empire the world had ever known.