To me, the most remarkable thing about the Koran is how progressive it is. I write with great humility as a member of another faith. As an outsider, the Koran strikes me as a reforming book, trying to return Judaism and Christianity to their origins, much as reformers attempted to do with the Christian church centuries later. The Koran is inclusive. It extols science and knowledge and abhors superstition. It is practical and far ahead of its time in attitudes toward marriage, women, and governance.
Under its guidance, the spread of Islam and its dominance over previously Christian or pagan lands were breathtaking. Over centuries, Islam founded an empire and led the world in discovery, art, and culture. The standard-bearers of tolerance in the early Middle Ages were far more likely to be found in Muslim lands than in Christian ones.