This manual, Army Regulation AR 20-1 Inspections, Assistance, and Investigations: Inspector General Activities and Procedures February 2018, prescribes policy and procedures concerning the mission and duties of The Inspector General (TIG). It also prescribes duties, missions, standards, and requirements for inspectors general (IGs) throughout the Army. Responsibilities are prescribed for commanders; State Adjutants General (AGs); and heads of agencies, activities, centers, and installations for the support of IG activities.This regulation prescribes the responsibility and policy for the selection and duties of inspectors general throughout the Army. It describes inspector general functions, including teaching and training, inspections, assistance, and investigations. Although the fundamental inspector general role and functions have not changed, this revision incorporates numerous policy and mandated procedural changes affecting inspector general activities. This regulation implements DODD 5505.6.