This illuminating book explores the nature of international humanitarian law (IHL), so doing by asking whether it should be seen as a permissive or a restrictive regime. An experienced lawyer in the field, Anne Quintin offers an in-depth expert analysis of this highly debated topic. In the eyes of many, the primary purpose of IHL is to impose restrictions on the actions of parties in armed conflicts, in order to protect victims. But IHL is also increasingly cited as an authority in permitting conduct that would be deemed unlawful in peacetime, for instance some cases of internment or targeting of persons. Considering both international and non-international armed conflicts, Quintin carefully and astutely peels away the layers of this debate, revealing the true nature of IHL and concluding that whilst IHL initially developed as a restrictive regime composed of prohibitions and prescriptions, it nevertheless contains within it rare permissions that allow states to act. Utilising a scientific methodology to offer concrete and realistic outcomes, whilst couching differing interpretations of IHL in wider debates surrounding the nature of international law, this book will be of interest to all academics, practitioners and policy-makers in the field of international humanitarian law. Its analysis of how people are effectively protected during an armed conflict will also be beneficial for the wider humanitarian community.