This book focused on the concept and contours of Non-International Armed Conflict under international law. Its primary purpose was to provide normative and doctrinal guidance for identifying NIACs in real-time in order to determine the applicable frameworks of international law. The concept of NIAC emerged from the adoption of the four Geneva Conventions of 1949 as an inverse formulation (not of an international character) of an indeterminate concept (armed conflict) foreign to the lexicon of IHL. This lack of clarity provided states with decades of broad discretion to either deny or assert the existence of a NIAC, regardless of the prevailing facts on the ground. Some 70 years later, the concept of NIAC has evolved considerably through various developments in international law and practice, although has not been stretched beyond its normative or legal foundations. At its most basic, a NIAC is an armed conflict between a state and a non-state actor, or between two or more non-state actors absent the involvement of a state. Accordingly, a NIAC is defined on the basis of the legal status of the opposing Parties as opposed to its territorial delineations, and therefore should not viewed as an internal armed conflict. This book provided a comprehensive and critical analysis of six elements of NIAC, which formed into six distinct Chapters.