The regulation's provisions apply to the Department of Defense and to other Federal agencies. They are written in terms of the most common situation where a contractor has access to or possession of classified information in connection with the performance of a classified contract. An introduction explains the scope and use of the regulation, its applicability to subcontractors, and its applicability to contractors in foreign countries. Additional sections cover the definition of terms, procedural and organizational requirements, communications security, and procedures relating to commercial carriers. Personnel and facility clearances and denials, the handling of visitors to agencies, security inspections, and international security programs are also covered. Footnotes, forms and appendixes presenting additional forms and guidelines are included. A glossary of acronyms and abbreviations and an index are also supplied.