The quagmire that is modern-day Syria is as infinitely complex as it was when it emerged from the ruins of the Ottoman Empire. Its medley of cultures and ethnicities coexisted peaceably under the sultans, but the European powers that inherited the land after World War I were unfamiliar with -- and uninterested in protecting -- Syria's unique brand of pluralism. Decades of autocratic rule followed. Today, the warring factions that populate the Syrian battlefield speak to the unraveling of Syria's once-cohesive society, but the lessons of the Ottoman empire remain. Moving forward, those lessons may be the best hope for turning a failed state into a nation at once unified and diverse....