Army field manual (FM) 4-40, Quartermaster Operations, is the revision of the obsolete FM 10-1, Quartermaster Principles. FM 4-40 provides logisticians and field commanders an understanding of Quartermaster principles, organizations, and procedures within the context of decisive action. The manual provides basic doctrinal discussion on the organization and operations of Quartermaster units within the Army. This manual updates FM 10-1, incorporating modular unit capabilities, designs and concepts, plus updated terminology IAW ADP 3-0 and ADRP 3-0 and other commensurate doctrine into FM 4-40. In rewriting the manual, chapter content on individual commodity areas was consolidated to produce three chapters from 19 chapters: one covering fundamentals, one covering all supply functions, and one covering field services. The net effect was to reduce the manual from 130 pages to 60 pages. Other key changes in this manual include the addition of a foreword to highlight the importance of the Global Combat Support System - Army, the identification of strategic partners that support Quartermaster functions, expanded discussion of supply chain management, and operational energy. The FM also addresses modernization in both the aerial delivery and mortuary affairs force designs. The manual also further expands on the two Quartermaster core competencies; supply and field services. FM 4-40 contains three chapters: Chapter 1 provides an overview of Quartermaster Operations. This chapter describes the Quartermaster functions, enabling organizations and mission command systems. The fundamentals of logistics command systems and how they enable commanders to gain a common operational picture is also noted. Chapter 1 defines support relationships, management functions, and requirements for total asset visibility. Chapter 2 discusses supply operations, reviews classes of supply, discusses multi-modal operations, and establishes an overview for unit supply operations. Specifically, mentioned are distribution hubs, supply support activities, accountability and responsibility, property records, inventories, and adjustments reports. Chapter 3 discusses Quartermaster Field Service Operations and how they are employed and generate combat power for the combatant commander. The chapter provides a brief overview of aerial delivery, clothing and textile repair, food services, shower and laundry, mortuary affairs, water purification, and force provider. FM 4-40 was developed in close coordination with the United States Army Combined Arms Support Command and Quartermaster School. Quartermaster Warrant Officer Advanced Course Students provided input based on their personal experiences as well as comments and input taken throughout the Army sustainment community. This publication, Field Manual FM 4-40 (FM 10-1) Quartermaster Operations, provides fundamental guidance for the employment of United States (U.S.) Army quartermaster organizations deployed in support of joint and multinational operations across the spectrum of conflict. The principal audience for field manual (FM) 4-40 is personnel of all grades and levels performing in quartermaster positions. FM 4-40 establishes Army doctrine for quartermaster operations by providing overarching doctrinal direction for quartermaster operations conducted in support of decisive action detailed in other Army manuals. FM 4-40 also provides a foundation for the development of appropriate tactics, techniques, and procedures. Commanders and staffs of Army headquarters serving as joint task force or multinational headquarters should also refer to applicable joint or multinational doctrine concerning the range of military operations and joint or multinational forces. Trainers and educators throughout the Army will also use this manual.