Ever since World War II, countries have been reluctant to officially declare war on one another, even after they appear to be fighting one. Because a declaration of war brings burdensome legal consequences, the simplest approach is to find a euphemism to describe the conflict. In this intriguing book, Fazal argues that this is a consequence of the separation between the lawyers who write international humanitarian law and the military personnel who have to follow it. As a result, the laws have become so complex and demanding that even states that intend to comply with them sometimes struggle to do so. The situation has been further complicated by the rise of civil wars, for which the laws of war were not designed. The idea that ill-judged regulations can produce perverse incentives is not new, but Fazal’s analysis of this tendency within the laws of war skillfully blends quantitative and qualitative methods to produce something genuinely original.