Military history is the study of armed conflict in the history of humanity, and its impact on the societies, cultures and economies thereof, as well as the resulting changes to local and international relationships.
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.