Humanitarian aid represents a commitment to support vulnerable host populations that have experienced a sudden emergency and/or require ongoing assistance to improve quality of life. Over the past fifteen years humanitarian agencies, private organisations, governments, corporations, individuals and other stakeholders have proliferated, along with differing values, goals, strategies, actors and activities. Despite good intentions and successes this complex field with diverse mandates, people, time lines, funding and absence of clear definitions to describe specific identities, presents a chaotic and confusing image to the public, host governments, recipients and ongoing challenges for agencies and aid workers. Weak coordination, erratic funding and differing roles often lead to expensive duplication of services, wasted resources and present serious credibility and survival issues to agencies that depend on donor funding to save and improve the lives of the vulnerable. Hence this paper deconstructs the roles of and linkages between emergency, relief, rehabilitation and development aid, identifies problems that impact on effectiveness and sustainability and points to progress and achievements over the past fifty years.