Professional historians normally focus on military affairs that had a major impact on the societies involved as well as the aftermath of conflicts, while amateur historians and hobbyists often take a larger interest in the details of battles, equipment and uniforms in use.
The essential subjects of military history study are the causes of war, the social and cultural foundations, military doctrine on each side, the logistics, leadership, technology, strategy, and tactics used, and how these changed over time. On the other hand, Just War Theory explores the moral dimensions of warfare, and to better limit the destructive reality caused by war, seeks to establish a doctrine of military ethics.
As an applied field, military history has been studied at academies and service schools because the military command seeks to not repeat past mistakes, and improve upon its current performance by instilling an ability in commanders to perceive historical parallels during a battle, so as to capitalize on the lessons learned from the past. When certifying military history instructors the Combat Studies Institute deemphasizes rote detail memorization and focuses on themes and context in relation to current and future conflict, using the motto "Past is Prologue."
The discipline of military history is dynamic, changing with development as much of the subject area as the societies and organisations that make use of it. The dynamic nature of the discipline of military history is largely related to the rapidity of change the military forces, and the art and science of managing them, as well as the frenetic pace of technological development that had taken place during the period known as the Industrial Revolution, and more recently in the nuclear and information ages. An important recent concept is the Revolution in Military Affairs (RMA) which attempts to explain how warfare has been shaped by emerging technologies, such as gunpowder. It highlights the short outbursts of rapid change followed by periods of relative stability.
In terms of the history profession in major countries, military history is an orphan, despite its enormous popularity with the general public. William H. McNeill points out:
Historiography is the study of the history and method of the discipline of history or the study of a specialised topic. In this case, military history with an eye to gaining an accurate assessment of conflicts using all available sources. For this reason military history is periodised, creating overlaying boundaries of study and analysis in which descriptions of battles by leaders may be unreliable due to the inclination to minimize mention of failure and exaggerate success. Military historians use Historiographical analysis in an effort to allow an unbiased, contemporary view of records.
One military historian, Jeremy Black, outlined problems 21st-century military historians face as an inheritance of their predecessors: Eurocentricity, a technological bias, a focus on leading military powers and dominant military systems, the separation of land from sea and recently air conflicts, the focus on state-to-state conflict, a lack of focus on political "tasking" in how forces are used.