Since the end of the Cold War, humanitarian activity has grown exponentially. Several factors today seem to demonstrate profound changes in this polymorphic sector. These are factors related first to the development of crises and vulnerabilities and the risks that are emerging, second to the environment around humanitarian action and the contemporary challenges to compliance with humanitarian principles, law, and access to victims, and third to new methods and changes in the composition of the sector itself. In this edition, the Review gives the floor to representatives of a number of humanitarian operational organizations and research centres to discuss each of these three aspects of change that we think are critical to the future of humanitarian action.