This publication, Army Techniques Publication ATP 3-05.2 Foreign Internal Defense August 2015, provides the U.S. Army commanders and staffs information on the concept of planning and conducting foreign internal defense (FID). ATP 3-05.2 describes the fundamentals, activities, and considerations involved in the planning and execution of FID throughout the full range of military operations, and it emphasizes FID as a strategic policy option. This publication serves as the doctrinal foundation for subordinate Army FID doctrine, force integration, materiel acquisition, professional education, and individual and unit training. This publication also serves as the Army's description of FID, which will be useful in the larger joint and interagency environment. The principal audience for ATP 3-05.2 is all members of the profession of arms. Commanders and staffs of Army headquarters serving as joint task force (JTF) 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 publication. ATP 3-05.2 (formerly FM 3-05.2) was last published in 2011. This revision provides special operations forces (SOF) commanders; their staffs; other Services in the Department of Defense (DOD); and joint, interagency, intergovernmental, and multinational audiences, as well as supporting and supported agencies and organizations techniques for providing support to FID operations. The publication provides doctrinal guidance and outlines the necessary requirements for conducting, planning, preparing, and executing missions. Chapter 1 provides an overview of the organization and functions of FID, including the HN internal defense and development (IDAD) program, a comprehensive approach of FID. It also describes the relationship with other operations and U.S. national objectives and policy throughout the range of military operations. Chapter 2 discusses organization and responsibilities from national-level organizations to the U.S. diplomatic mission and country team and down to the JTF. Also covered is the role of conventional forces in FID and the multinational forces. Chapter 3 discusses planning processes and considerations, with a focus on guidance, planning requirements, assessment, and other key operational considerations. Chapter 4 provides an overview of requirements, organization, and support. This chapter includes a discussion of training, skills needed for success, training strategy, and advisory assistance to the HN. Chapter 5 discusses employment considerations and provides an overview of employment factors for SOF and conventional forces, health service support (HSS), and site survey procedures. Chapter 6 provides a discussion on overall operations, including indirect and direct support operations, combat operations, sustainment, and insurgency operations. Chapter 7 discusses redeployment considerations, such as termination of operations, handoff procedures, and postmission debriefing procedures. Appendix A covers legal, regulatory, and policy considerations; international law; U.S. and HN laws; treaties; and agreements. This appendix also covers United States Code (USC) for funding. Appendix B discusses the HN's IDAD strategy and program, including the four functions of IDAD and the principles that apply to the program. Appendix C covers intelligence support operations, with discussions on the role of intelligence in FID and intelligence requirements. Appendix D discusses the illustrative interagency plan, including the content, phases, joint, and Army planning and concerns. Appendix E discusses security assistance operations and how the geographic combatant commander (GCC) uses security assistance to further FID activities. Appendix F covers site survey considerations and checklist to help during the predeployment site survey.