Since it seemingly recent arrival on the world stage, the Islamic State, or IS, has set itself apart even from other radical groups in the Middle East. In short order, it has become perhaps the most pressing security concern in the region, a powerful and unpredictable new kind of jihadi threat with a reputation for exceptional public brutality, slick propaganda, and military success. But observers have also noted something else: a surprising level of structure. The group takes a bureaucratic, systematized approach to maintaining power that makes it look in some ways more like a settled government than a fly-by-night band of extremists. Whether under the flag of the Islamic State, or ISIS before that, the group organizes the territory it administers into well-defined geographic units, levies taxes in areas it controls, and manages large numbers of fighters across a sparsely populated territory roughly the size of the United Kingdom.