Chapter 1 shortens the discussion of the operational environment found on the now obsolete 2011 FM 3-0, Change 1, and emphasizes military operations. This chapter provides a framework of variables of an operationalenvironment that shape their nature and affect outcomes. The chapter then discusses unified action and joint operations as well as land operations. Finally, this chapter discusses law of land warfare and combined arms.Chapter 2 introduces the Army's new operational concept of unified land operations. It discusses how commanders apply landpower as part of unified action to defeat the enemy on land and establish conditions that achieve the joint force commander's end state. Chapter 2 discusses how commanders demonstrate the Army's new core competencies of combined arms maneuver and wide area security conducted through decisive action.Chapter 3 discusses combat power and the warfighting functions used to generate combat power in support of unified land operations. As in the now obsolete 2011 FM 3-0, Change 1, chapter 3 discusses the eight elements of combat power that include the six warfighting functions with leadership and information. Lastly, it discusseshow Army forces achieve combined arms through force tailoring, task organization, and mutual support.Chapter 4 discusses the elements of operational art and the meaning of operational art to Army forces. It elaborates on commanders and staffs applying the elements of operational art to understand, visualize, and describe how to establish conditions to achieve a desired end state. It discusses how operational art represents a creative approach to dealing with the direction of military forces and expresses an informed vision across the levels of war.