This publication, Army Techniques Publication ATP 3-34.23 Engineer Operations - Echelons Above Brigade Combat Team June 2015, describes engineer operations at echelons above brigade (EAB) combat team level. It is the doctrinal manual for engineer support to division, corps, and theater Army echelons. This manual is an extension of FM 3-34 and is linked to joint and Army doctrine to ensure that it is useful for operational commanders and staffs. This manual serves as a guide for the application of engineer combat power and the employment of engineer forces in support of decisive action primarily at higher echelons and within a joint framework. The principal audience for ATP 3-34.23 is engineer commanders and trainers at higher echelons. This manual forms the foundation for the engineer curriculum contained in the engineer portions of the Army Education System. The information contained in this manual will assist multinational forces and other Services and branches of the Army in planning and integrating engineer capabilities. This manual will also assist Army branch schools in teaching the integration of engineer capabilities into Army and joint operations. This manual describes the engineer operations integrated through the warfighting functions in a combined arms application of combat power. It describes the engineer capabilities available to commanders and provides information for force-tailoring these capabilities at higher echelons to ensure synchronization throughout the operations process and across the range of military operations. It discusses the foundation of engineer operations to ensure integration at each echelon and develops considerations for engineer operations within the operations process, tailored organization, range of military operations, and headquarters configuration unique to the division, corps, and theater Army echelons. This manual emphasizes the simultaneous combination of offensive, defensive, and stability or defense support of civil authorities (DSCA) tasks. It describes engineer support to Army forces conducting decisive action within the framework of joint operations. It also addresses the engineer roles and functions with unified action partners (potentially under multinational or interagency leadership) and within diverse command relationships. The manual is organized into 5 chapters and 3 appendixes that provide additional details on selected operational topics. A brief description of each chapter is below: Chapter 1 describes the engineer view of the operational environment as it pertains to operations at EAB combat team. It describes the forces and capabilities available (including unified action partners) and addresses the tailoring of engineer force pool capabilities in support of engineer operations. Chapter 2 lays the foundation for engineer operations at EAB. It focuses on integration at each echelon and throughout the operations process. It discusses the engineer staff by echelon, capabilities within the engineer disciplines, and synchronized application of these capabilities through the warfighting functions. Chapter 3 describes engineer operations at the theater echelon. It discusses integration into the theater Army design methods, force-tailoring considerations at the theater echelon, and engineer support in each of the operational configurations described for a theater Army headquarters. Chapter 4 describes engineer operations at the corps echelon. It discusses integration into the corps operations processes, force-tailoring considerations, decisive action at the corps echelon, and engineer support in each of the operational configurations described for a corps headquarters. Chapter 5 describes engineer operations at the division echelon. It discusses integration into division operations processes, force-tailoring considerations, decisive action at the division echelon, and engineer support in each of the operational configurations described for a division headquarters.