This publication, Field Manual FM 3-57 Civil Affairs Operations April 2019, provides Army commanders with the information necessary for the integration of Civil Affairs (CA) capabilities in support of unified land operations. It also provides the doctrinal basis for the conduct of Civil Affairs operations (CAO) in support of civil-military operations (CMO). FM 3-57 clarifies the role of CA forces in the execution of CAO, and in support of CMO, with regard to the missions, employment, support requirements, capabilities, and limitations of these forces. CA forces execute CAO in support of unified land operations in all theaters across the range of military operations to achieve unified action. A force multiplier for every commander, CA forces are one of the primary resources a commander has to assist in dealing with the complex and ever-changing civil component of the operational environment (OE). CA forces are trained, organized, and equipped to plan, execute, and assess CAO in support of Army and joint operations. Their cultural orientation, regional expertise, linguistic capabilities, advisory ability, and civilian acquired professional skills paralleling common government functions are essential elements to the successful completion of the commander’s mission. The principal audience for FM 3-57 is the leadership of the Army, officers, and senior noncommissioned officers who command Army forces or serve on the staffs that support those commanders of operations at all levels of war. It is also an applicable reference for the civilian leadership of the U.S. interagency organizations. Although written primarily to assist the Army Service component command, Army corps, Army divisions, brigade combat teams, and maneuver enhancement brigades with the integration of CAO in planning, preparing for, executing, and assessing unified land operations, this FM is applicable for joint force operations as well. FM 3-57 applies to the Active Army, the Army National Guard/Army National Guard of the United States, and the United States Army Reserve (USAR) unless otherwise stated. The proponent of FM 3-57 is the U.S. Army Special Operations Center of Excellence, USAJFKSWCS.