Prisoners of war are traditionally members of the armed forces of a belligerent who have been captured by an enemy. In modern warfare the term also includes members of partisan, or guerilla, groups that operate according to the rules of war, civilian contract supply and labor personnel, war correspondents, and crews of merchant vessels.

    The cardinal rule regarding prisoners of war and also interned civilians is that they be treated humanely. In the passion of war this rule is usually violated. The degree of violation varies according to the particular circumstances and the inhibitions imposed by behavior. In ancient times prisoners of war were killed or sold into slavery. The medieval period brought a stress on ransom, and early modern time's exchange. The practice of exchange lasted until the American Civil War, but was finally stopped by the North in an effort to drain South of manpower. Prisoners of war in the 20th century have usually had to escape in order to regain their freedom before the end of the conflict.

    Conventions to draw up rules for the treatment of prisoners of war, especially with the respect to food, housing, and conditions of work, were held in Brussels in 1874, at The Hague in 1899 and 1907, and at Geneva in 1949.In the Korean War the Chinese Communists used prisoners, especially Americans, for propaganda purposes after subjecting them to brainwashing. The result, in the United States, was the 1955 Prisoner of War Code, which spelled out the responsibilities of captured American servicemen.

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