This publication provides guidance on planning, implementing, and evaluating systems and measures in a State in order to detect nuclear and other radioactive material out of regulatory control in the State’s interior by means of instrument alarms and information alerts. The guidance covers the planning of detection operations, equipment deployment and human resource development. This publication is intended for authorities responsible for designing, implementing, and sustaining nuclear security systems and measures within a State, such as personnel from the Ministry of Interior, Law Enforcement Agencies, Health Authorities, National Regulators, Emergency Response, and National Security Organizations.