This book analyses the multi-faceted impact armed conflict has on investment treaties. Refuting the common association of the outbreak of hostilities with the termination or suspension of treaties, it not only makes a case for the continuity of investment treaties. The book argues that the impact of armed conflict on such agreements goes far beyond these questions: Changed factual circumstances and public interests as well as international humanitarian law heavily influence the application and interpretation of investment protection standards. The book argues that investment treaties can and must channel these effects to remain effective during armed conflict and strike a fair balance between investor and public interests. It shows ways in which contextual and systemic interpretation, respect for reasonable state action, and careful treaty design can ensure that investment treaties continue to fulfil their purpose of strengthening compliance with legal rules also in times of armed conflict.