During the past two decades, environmental security and more specifically the security of water as a natural resource has come to the forefront of research and discussion. Many regions have experienced an increased water scarcity due to climatic variability and climate change, and the uncertain impacts of climate change to the supply has brought the issue to the centre of political debates. Indeed it has been raised by both the EU and the US national governments as a major issue of concern globally and has also been highlighted by the Security Council of the UN. The four volumes of this collection seek to broadly outline the debate as it has developed, both from a policy as well as an academic perspective, with the aim to bring conceptual clarity as well as provide an account of how the water security discourse has emerged and developed. Volume One: Water Security - Origin and foundationsVolume Two: Water Security - International conflict and cooperationVolume Three. Water Security and Development - An intimate relationVolume Four: The Age of Water Security - Current dilemmas and future challenges.