Kilcullen has a rare ability to combine serious theory with the insight of an experienced practitioner. He argues that most future conflicts will occur in cities, thanks to the extraordinary growth in urban populations and the interconnectedness wrought by new technologies, which will create novel opportunities for crime and political violence. Kilcullen brings his narrative to life by using contemporary examples, including the recent revolts in Libya and Syria and the 2008 terrorist attacks in Mumbai. The density of contemporary cities makes it easier for gangsters and warlords to assert control and renders civilian populations highly vulnerable. Security forces can address such threats, but as Kilcullen notes, a lack of popular support can make intensive search-and-destroy measures counterproductive. Kilcullen’s book would have benefited from more historical perspective. States have long coped with the particular challenges of urban security. Modern Paris was designed, in part, to help the authorities maintain order, and in Warsaw during World War II, anti-Nazi Polish resisters learned that states or armies can suppress a popular urban uprising so long as they care little about preserving life or property.