This manual provides an overview of electromagnetic spectrum operations for the Army at the strategic, operational, and tactical levels. This manual also provides direction, guidance, and techniques necessary to meet the needs of Army electromagnetic spectrum operations in a joint, interagency and multinational environment. In addition, this guide describes the roles and functions of international, national, host nation, and military organizations. It provides a comprehensive look at installation frequency coordination. The target audience for this manual is the electromagnetic spectrum manager, but it is also useful for signal leaders and supervisors to gain an understanding of electromagnetic spectrum operations. The most significant changes in this manual from the previous edition are in Chapters 1, 5, and 6. Chapter 1 has been revised to include the introduction of electromagnetic spectrum operations, the tenets that constitute electromagnetic spectrum operations, and an overview of how electromagnetic spectrum operations support full spectrum operations. Chapter 5 has been revised to include corps and below operations in addition to a better explanation of coordination with electronic warfare operations. Chapter 6 has been updated and revised substantially particularly in regard to equipment updates. Numerous minor updates and revisions have been included throughout the manual to reflect changes in organization, technologies, and processes.