The Islamic State, also known as ISIS, is more than a place or a terrorist group. It is a set of ideas rooted in centuries-old beliefs and wrapped in a philosophy of violence. Adherents believe they are an army of the righteous working to create an ideal state for today’s believers and fighting a war that is destined to end with the coming of Jesus and defeat of the Antichrist. Understanding them, Brian L. Steed says, is key to defeating them. A military historian at the U.S. Army Command and General Staff College at Fort Leavenworth and specialist on the Middle East, he initially spoke at the Library about the Islamic State in late 2014. He continues his examination, taking a close look at the militant group’s makeup, motivations, and operations.