In the mid-seventies, two events created a void in echelons above corps (EAC) intelligence doctrine and force structure: the transition of Army doctrine from field Army to EAC and the implementation of decisions resulting from the Intelligence Organization and Stationing Study. In 1982, the Army Chief of Staff approved the changes resulting from this document for planning purposes. During this time, US Army Intelligence and Security Command (INSCOM) completed the EAC Intelligence, Security, and Electronic Warfare Architecture Study. This was the base document for EAC intelligence and electronic warfare (IEW) force development. FM 100-16, published in April 1985, incorporated key IEW doctrinal principles. This manual applies those principles to the Military Intelligence (MI) brigades EAC) that support IEW in different theaters. The brigades are the critical parts of the IEW structure established at EAC. The IEW functions of the MI brigades EAC) forge the links with the EAC staff, the echelons above corps intelligence center EACIC), echelons corps and below (ECB), other MI brigade elements, other services, and national level intelligence agencies. This manual provides the doctrine for EAC IEW operations, including organizations, missions, functions, and capabilities of MI organizations at EAC. This manual further supports Army doctrine described in FM 100-5 and FM 100-20. This manual is not designed nor intended to be a descriptive tactics, techniques, and procedures (TTP) manual. The uniqueness of the EAC theaters in which the IEW units are located prohibits such a task. The geographical and operational focus of the theaters, along with command and National Command Authorities (NCA) guidance, orients the specific IEW support missions; for example, functional and regional tailoring to best achieve the assigned mission.