If the rise of Islamic State can overthrow powerful states in a matter of weeks, what kind of a secure future can the world expect? After more than a decade of the war on terror, security specialists thought that Islamist paramilitary movements were in decline; the threat from ISIS in Syria and Iraq, Boko Haram in Nigeria, al-Qaida in Yemen, the chaos in Libya and the return of the Taliban in Afghanistan have all shown that to be wishful thinking. Once again the West is at war in the Middle East. Paul Rogers, the distinguished global security specialist, provides a much-needed look at the rise of such global terrorist movements from the margins and presents a new argument as troubling as it is compelling. While Islamic State has taken root in the Middle East and North Africa and has increasing impact across the world as thousands of young men and women rally to its cause, Rogers argues that it should be seen not just as a threat in its own right but as a marker of a much more dangerous world riddled with irregular war.