This manual, elaborated jointly by the Inter-parliamentary Union (IPU) and the ICRC, is composed of three sections. The first chapter contextualises the issue of persons reported missing following an armed conflict or a situation of internal violence, and the impact on their families. The second chapter focuses on the essential role that parliamentarians can play in preventing disappearances, elucidating the fate of missing persons, and assisting their families. The third chapter contains an annotated version of the Model Law on the Missing drafted by the ICRC's Advisory Services, a tool that offers a comprehensive legal framework designed to help States and their competent national authorities to adopt or improve their national legislation on the Missing.