The security environment America faces today is extremely complex. While relationships may have improved between historic enemy nation states, the threat of symmetric force on force warfare still exists. The constant spread of violent extremists set on changing the world's geopolitical environment with destructive technology and weapons of mass destruction has evolved into major challenges America must be ready to defeat. These wide ranging threats against sovereign nations and the domains of land, maritime, air, space, and cyberspace, require different approaches towards attaining peace and security. Recognizing the engineering aspect of military operations cannot be overemphasized. The success of any military operation hinges on competent engineers guided by actions proven to be successful during previous operations. Although current and future threats may bring about changes in how military engineers from all Services are employed in joint environments, the primary mission of establishing and maintaining bases of support for the projection of airpower will remain the top priority for Air Force civil engineers. As we face uncertainty and persistent conflict, and increasingly focus on joint, interagency, and multinational operations, the demand for civil engineers and the need for engineer doctrine become increasingly important. Doctrine ensures Air Force civil engineers provide effective support to the commander of Air Force forces (COMAFFOR) and remain capable of rapidly responding to crises and other contingencies. This Air Force doctrine document (AFDD), "Engineer Operations (AFDD 3-34)," directly supports AFDD 1, Air Force Basic Doctrine, Organization, and Command, and AFDD 4-0, Agile Combat Support. It sets forth guiding principles on employing Air Force civil engineers at any level of warfare, strategic, operational, or tactical, under the command and control of the COMAFFOR, within any operational area including the homeland. It incorporates Air Force civil engineer doctrinal precepts, focusing on engineer fundamentals, organization and command, planning and execution, and capabilities. This document also supports all other Air Force doctrine and describes how the COMAFFOR employs engineer capabilities throughout all phases of military operations. This document is designed to assist the COMAFFOR, commanders, and planners to effectively integrate Air Force engineer capabilities into all types of military operations. It establishes doctrine and procedures for Air Force civil engineers as part of the Air Force's agile combat support, as well as engineers supporting civil, joint, or combined missions across the range of military operations. It is authoritative but requires judgment in application. It describes guiding principles to be used to organize and employ engineer capabilities to achieve strategic, operational, and tactical objectives. While the document speaks primarily to Air Force civil engineer support to Air Force missions, it is also organized in a manner that addresses Air Force civil engineer roles in joint, interagency, and multinational operations.