To bridge the widening gap between the theory and practice of the law, Modern Warfare brings together both scholars and practitioners who offer diverse perspectives on the key challenges to the law’s legitimacy: how to ensure compliance among non-state groups; the proliferation of private military companies in the employ of humanitarian organizations; tension between the idea of humanitarian space and counterinsurgency doctrines; and the phenomenon of urban violence. By bringing to light the law’s limitations – and potential – this timely book opens a path to preventing further unnecessary suffering and violence.