The book provides an up to date and authoritative account of how the UN is re[1]thinking its obligations to protect civilians during conflicts. Based on hundreds of interviews with senior UN officials and humanitarian protection staff in headquarters and in the field and a review of the UN´s ´grey literature´. It also draws on the author´s own experience of working on human rights and protection in some of the world´s most violent conflicts. It is written not about what the UN ought to do - or how it could have behaved differently in an abstract or theoretically ideal world - but what the UN is actually doing to fulfil the fundamental purposes set forth in its Charter.