ON JULY 6TH, 2005, in an unprecedented display of intersectarian collaboration, 170 of the world's leading Muslim clerics and scholars gathered in Amman, Jordan, to issue a joint fatwa, or legal ruling, denouncing all acts of terrorism committed in the name of Islam. This belated attempt by the traditional clerical institutions to assert some measure of influence and authority over the world's Muslims was surely one of the most interesting developments in what has become an epic battle to define the faith and practice of over a billion people. Never before in the history of Islam had representatives of every major sect and school of law assembled as a single body, much less come to terms on issues of mutual concern. Yet what made the Amman declaration so remarkable was not its condemnation of terrorism-since Sept. 11, 2001, similar statements have been issued by countless Muslim organizations throughout the world, despite perceptions to the contrary in the West. Rather, it was the inclusion of an all-encompassing fatwa reminding Muslims that only those who have dedicated a lifetime of study to the traditional Islamic sciences-in other words, the clerics themselves-could issue a fatwa in the first place. This statement was a deliberate attempt to strip Islamic militants like Osama bin Laden of their self-proclaimed authority to speak for the world's 1.3 billion Muslims. But if these clerics thought they could exert their authority over the militants, they were mistaken. The following day, July 7, four young British Muslims obliterated themselves and 52 bus and tube passengers during the height of rush hour. The London bombers, like the perpetrators of similar attacks in Madrid, New York, Tunisia, Turkey, Casablanca, Riyadh, Bali, Egypt, and, most dramatically, Iraq, believed they were heeding bin Laden's call for global jihad. No wonder, then, that since 9/11 bin Laden has taken on an almost mythic stature in the world's imagination as the undisputed leader of a unified global network of Islamic terrorism (more properly termed "jihadism"). Indeed, in President Bush's mind, bin Laden is a modern-day Hitler or Lenin. But in the minds of many scholars of Islam and observers of the Muslim world, bin Laden is not only a murderous criminal; he has transformed himself into one of the principal figures of what many now call "the Islamic Reformation." Obviously the term "reformation" has certain unavoidable Christian and European connotations that are simply not applicable to the complex sociopolitical conflicts plaguing much of the Arab and Muslim world. And any comparison of people and events in the 16th century to those of the 21st century must come with the caveat that historical analogies are never simple and should be handled with care. But the Christian Reformation, it should be remembered, was, above all else, an argument over who has the authority to define faith: the individual or the institution. In many ways, this same argument is now taking place within Islam, with similarly violent consequences. Despite common perception in Europe and the United States, bin Laden's primary target is neither Christians nor Jews (both of whom are referred to by Al Qaeda as "the far enemy") but rather Islam's traditional clerical institutions along with those hundreds of millions of Muslims who do not share his puritanical worldview ("the near enemy") and who, as a consequence, make up the overwhelming majority of Al Qaeda's victims. . . . To be sure, unlike Christianity, Islam has never had anything like a "Muslim pope" or a "Muslim Vatican." Religious authority in Islam is not centralized within a single individual or institution; rather, it is scattered among a host of exceedingly powerful clerical institutions and schools of law. This authority, it must be understood, is self-conferred, not divinely ordained. Like a Jewish rabbi, a Muslim cleric is a scholar, not a priest. His judgment on a particular issue is respected and followed not because it carries the authority of God, but because the cleric's scholarship is supposed to grant him deeper insight into what God desires of humanity. Consequently, for 1,400 years Islam's clerical institutions have managed to maintain their monopoly over religious interpretation by maintaining a monopoly over religious learning. That is no longer the case.