War diary

A war diary is a regularly updated official record kept by military units of their activities during wartime. The purpose of these diaries is to both record information which can later be used by the military to improve its training and tactics as well as to generate a detailed record of units' activities for future use by historians. War diaries are focused on the administration and operations of the unit they cover, and generally do not contain information about individual personnel.

The British Army first required that its units keep war diaries in 1907 as a means of preventing its mistakes of the Second Boer War from being repeated, and units currently operating in Afghanistan continue to maintain such diaries. The war diaries kept by Australian military units are normally maintained by the unit's adjutant or intelligence officer and contain a regularly updated narrative of its activities as well as copies of reports, messages received and maps.