War is not simply a military matter, but rather a complex phenomenon that affects all of society. The documentation of war is similarly complex. It appears in both public and private sources and in machine-readable, audio, and video-as well as paper-form, thereby presenting a considerable challenge to archivists concerned with the preservation of adequate documentation. Trends in research and interpretation can affect the demand for particular types of sources, but access to the archival record is often a greater obstacle to research than limitations on the nature or extent of the documentation. Archivists bear considerable responsibility for what the future will know of war in the twentieth century because that knowledge will depend to a large extent upon those fragments of the past that survive—the archival record.