Prisoners of war are not to be held in secret. Recording information aboutan individual’s detention serves to account for their whereabouts, therebyensuring that no one goes missing or is forcibly disappeared. The fact of aprisoner of war’s capture must be communicated at the earliest possiblemoment following capture, and within certain time limits, to the prisoner’sfamily and to the Central Prisoners of War Agency (now known, and hereinreferred to, as the Central Tracing Agency, which has always functionedunder the responsibility of the ICRC). Information regarding the capture,together with certain other details, is provided in a number of ways. One ofthese is through the cards that are the subject of the present article.