The Crusades happened almost a thousand years ago—why do they still provoke an argument? Osama bin Laden has used them to attempt to rally the Islamic world to his cause; President Bush has called the war on terrorism a "crusade." But what is the truth about the Crusades? Were they motivated by savage greed and intolerance or by pious idealism? Were they an unprovoked attack by the West on the Islamic world or a reaction to centuries of Islamic incursions? How should we understand the legacy of the Crusades today, in a time of conflict between the West and radical Islamic terrorists?