text: Introduction
  The publication of FM 3-0 in October 2022 codified multidomain operations as the Army’s operational
  concept. FM 4-0 describes sustainment operations in support of the Army’s operational concept and how the
  Army supports the joint force in the execution of campaigns. It is the Army’s doctrine for sustainment
  operations across the competition continuum at the theater strategic, operational, and tactical levels of
  warfare. This publication emphasizes sustainment fundamentals and tactics to provide all commanders,
  staffs, and Soldiers an understanding of sustainment operations. The contents of FM 4-0 are consistent with
  the principal sustainment doctrine contained in ADP 4-0 and serve as the doctrinal foundation for all Army
  sustainment operations. FM 4-0 describes how the Army and its organizations conduct sustainment
  operations and is the keystone Army doctrine reinforced in Army techniques publications including ATP
  4-91, ATP 4-92, and ATP 4-93.
  The doctrine discussed in this manual is nested with the FM 3-0 series doctrine. Sustainment is crucial to the
  success of operations. The endurance of Army forces is primarily a function of their sustainment (ADP 3-0).
  Sustainment determines the depth and duration of Army operations. It is essential to seizing, retaining, and
  exploiting the initiative. Sustainment is inherently joint and facilitates the joint force commander’s ability to
  enable freedom of action, extend operational reach, and prolong endurance. Sustainment must be planned,
  integrated, and synchronized with operations at every level of warfare. Sustainment is dependent upon joint
  and strategic integration and should be coordinated to ensure resources are delivered to the point of
  employment. The Army’s sustainment capabilities assist in providing crucial operational area opening
  functions enabling joint forces to achieve strategic and operational reach. Army sustainment capabilities
  provide the bulk of Army support to other Services, common-user logistics, and other common sustainment
  resources in support of the combatant commander.
  The logic chart in the introductory figure on the next page is better understood if read from top to bottom.
  The chart depicts the peer threats and methods expected to be employed and the characteristics of the
  anticipated operational environment. The logic chart reflects the joint operational concept of unified action
  and defines multidomain operations as the Army’s operational concept and how the sustainment warfighting
  function contributes to unified action. The logic chart displays the strategic context through which forces
  conduct operations and how sustainment capabilities are task organized to support operational forces at
  echelon across all domains. The chart concludes by portraying how sustainment of large-scale combat
  operations requires integration into the operations process to enable freedom of action, extend operational
  reach, and provide the prolonged endurance necessary to accomplish missions, consolidate gains, and win
  our nation’s wars.