What are the main challenges that humanitarian actors face in upholding a principled approach in today's crises and emergencies? How are "principles guiding humanitarian action" understood by different actors and used in contemporary field realities? These are the questions to which the Review sought a response in this issue. The contributions highlight three important dimensions of the principles guiding humanitarian action: (1) they function simultaneously as "tools to do the job" - providing a compass to navigate through difficult choices in situations of conflicts and violence (2) as "identity catalysts" – resulting from the experience of humanitarian workers, principles in turn contribute to shaping the humanitarian sector's identity and boundaries , and (3) as an "ethos in action" – they are not only principles of humanitarian actors, they are humanitarian principles; the call to uphold human dignity, embedded in the principle of humanity, can and should be heeded by all of us.