Since September 2001, the United States has waged what the government has called "a global war on terror." Cassidy argues that what we are engaged in is a global insurgency and counterinsurgency. Al Qaeda and its affiliates comprise a novel and evolving form of networked insurgents who operate globally. They have harnessed the advantages of globalisation. They employ terrorism as tactics, subsuming this terror within their overarching aims to undermine the Western system of states. Placing the war against al Qaeda and its allied groups and organisations in the context of a global insurgency also presents implications for doctrine, interagency coordination, and military cultural change. The current war is an evolving insurgency of a new kind. While it has some similarities to twentieth century revolutionary guerrilla war, it is also distinct. The author combines the foremost maxims of the most prominent philosophers of war to arrive at this threefold overarching theme: know the enemy, know yourself, and know what kind of war you are embarking upon. Thus, he first offers a distilled analysis of al Qaeda and its associated networks, with a particular focus on ideology and culture. Next, he details the challenges that big powers face when they prosecute counterinsurgencies, using examples from Russian, American, and British counterinsurgent wars during and before the twentieth century.