This publication, Army Techniques Publication ATP 1-20 Military History Operations Change 1 August 2015, is the first historical ATP released under Doctrine 2015. It replaces FM 1-20. ATP 1-20 makes numerous changes from the now obsolete FM 1-20. ATP 1-20 includes a discussion of how the Army organizes for field history operations to ensure that Army operations are captured for the historical record. The most significant change is the introduction to the various types of military history detachment (MHD) organizations and doctrinal missions. ATP 1-20 also delineates the principles field historians follow to execute their duties. ATP 1-20 contains six chapters: Chapter 1 discusses the Army Historical Program and its component parts, outlines the duties and responsibilities of each element in the Army Historical Program, identifies the responsibilities of commanders for performing command and unit history programs, and discusses field history during Army operations and at home station. Chapter 2 discusses the integral role of military history, and provides guiding principles for field historians to follow when performing their duties and responsibilities. Chapter 3 discusses how the Army organizes field history operations and the duties and responsibilities of historians at each level in the chain of command. It outlines other organizations within the Army and the joint force that contribute to Army field history operations. Chapter 4 outlines MHD historical development, discusses how an MHD is organized, and discusses how MHDs are employed during combat and contingency operations. Chapter 5 discusses the sources and types of historical materials collected by field historians with emphasis on documents, oral interviews, and artifacts. It also provides guidance on historical reporting, both formal and informal, at the various levels of the chain of command. Chapter 6 This chapter describes the military decisionmaking process (MDMP) and planning as it applies to performing field history operations. ATP 1-20 has five appendices that provide guidance on reports and forms. Terms for which this manual is proponent and modified Army terms have been added. Army Techniques Publication 1-20 discusses field history operations and provides guidance on the organization and employment of Army historians. It details the techniques and procedures for the documentation, recording, and preservation of the official history of the Army during combat and contingency operations. The principal audiences for ATP 1-20 are Army commanders, staffs, leaders, and those Soldiers and civilians assigned to historical duties. It outlines responsibilities for commanders and units and the necessary doctrinal guidance for unit historical officers (UHO), military history detachments (MHD), and other field historians to perform historical tasks across the range of military operations. ATP 1-20 helps commanders, and Army field historians assigned to them, with their responsibilities to ensure that Army operational history is captured and preserved, with particular attention to command and unit history officers and MHDs. It is applicable at all command levels of the operational Army that may deploy and perform combat and contingency operations. The doctrinal principles and procedures in this publication provide guidance and are not prescriptive. However, they reflect hard lessons learned over the course of Army history, especially when its operational history was not adequately captured or preserved.