This War Report provides detailed information on every armed conflict which took place during 2013, offering an unprecedented overview of the nature, range, and impact of these conflicts and the legal issues they created. In Part I, the Report describes its criteria for the identification and classification of armed conflicts under international law, and the legal consequences that flow from this classification. It sets out a list of armed conflicts in 2013, categorising each as international, non-international, or a military occupation, with estimates of civilian and military casualties. In Part II, each of the 28 conflicts identified in Part I are examined in more detail, with an overview of the belligerents, means and methods of warfare, the applicable treaties and rules, and any prosecutions for, investigations into, or robust allegations of war crimes. Part III of the Report provides detailed thematic analysis of key legal developments which arose in the context of these conflicts, allowing for a more in-depth reflection on cross-cutting questions and controversies. The topics under investigation in this Report include US policy on drone strikes, the use of chemical weapons in Syria, the protection of persons with a disability, and national and international war crimes trials.The Report gives a full and accessible overview of armed conflicts in 2013, making it the perfect first port of call for everyone working in the field.