This Manual is composed of four volumes, each containing its own purpose. The purpose of the overall Manual, as authorized by DoD Directive (DoDD) 5143.01 (Reference (a)) and DoD Instruction (DoDI) 5200.01 (Reference (b)), is to reissue DoD 5200.1-R (Reference (c)) as a DoD Manual to implement policy, assign responsibilities, and provide procedures for the designation, marking, protection, and dissemination of CUI and classified information, including information categorized as collateral, sensitive compartmented information (SCI), and Special Access Program. This guidance is developed in accordance with Reference (b), Executive Order (E.O.) 13526 and E.O. 13556, and part 2001 of title 32, Code of Federal Regulations (References (d), (e), and (f)). This combined guidance is known as the DoD Information Security Program. This Volume (Volume 4) provides guidance for the identification and protection of CUI (Controlled Unclassified Information).