The security concerns of the United Nations today extend far beyond what the writers of the 1945 Charter could have imagined. As a result, the UN has been compelled to reconsider the parameters of what constitutes a threat to international peace and security, and what it means to be safe and secure in the twenty-first century. This text critically assesses the capacity of the UN to evolve in response to changing notions of security, and examines the complex history of people, places and politics that have helped shape this important global actor.