This course will focus on the concept of war in international law and as applied today in national law. We will cover the material in my new book 'War'. Starting with a look at the continuing relevance of the concept of war we will then examine the role of Declarations of War and the law on neutrality. We then turn to how war became outlawed as an institution within international law and the use of force became regulated through the UN Charter and the codification of the crime of aggression under the Statute of the International Criminal Court. There will be particular attention paid to the scope to the War Powers Act in the US and the different powers that are assumed in some national legal systems in time of War (formally understood). Turning to the application of humanitarian law and the principles applicable to the conduct of hostilities, the focus is on the underlying idea of war - as has occurred with the notion of 'law of war detainees' in Guantanamo and Afghanistan and the targeting of objects and people from ISIS and other groups directly contributing to the 'war sustaining economy'. A particular feature will be a detailed look at the traditional law of economic warfare at sea which allows for the seizure of enemy property and interception of all shipping to seize 'contraband of war' and those ships that breach blockade. Lastly we look at recent developments concerning war reparations and accountability for war crimes. The aim is to consider the whole of the law of war as well as to evaluate the uses and abuses of the concept of war in law.