Yonah Alexander and Dean Alexander’s book The Islamic State: Combating the caliphate without borders adds an interesting addition to the growing canon on the Islamic State (IS). It sets out to ‘address the current gap in realistic assessment regarding the IS threat, the risk it poses, and its broader implications at national, regional, and global levels’ and it does so by meticulously tracing the group’s tactics and strategy. In doing so, Alexander and Alexander rely heavily on data extracted from statements by government, military, and law-enforcement officials as well as newspaper sources. They compile an impressive and thorough amount of data to evaluate the current threat by the IS.... The Islamic State provides an invaluable resource for further research, thoroughly mapping both attacks by the IS as well as counteractions taken by the international community.