The effective search for the missing and identification of persons, alive or dead, are core components in the prevention and in resolving the issue of Missing Persons. The proper management and identification of human remains are also essential for the protection of the dead and the respect towards their families. Despite the growing literature on this topic, there is still a lack of publications describing the Identification as a process that includes different phases inherently composed of investigative, criminalistic and scientific forensic principles for both living and deceased unidentified individuals. This reference document aims to present the Identification process as an overarching concept that includes the search or preliminary investigation phases of the missing in any state (dead or alive), in any scenario (with or without bodies), with an integrated, multidisciplinary, and multiagency approach for implementation by all actors involved in the investigation and identification phases of missing persons and unidentified individuals.