This directive reissues and updates the responsibilities and functions of the Under Secretary of Defense for Intelligence (USD(I)), outlining its authority under various laws and presidential guidance. It establishes the USD(I) as the principal advisor on intelligence matters and mandates oversight of several defense intelligence agencies and programs while ensuring alignment with national security policies. The directive also delineates the USD(I)'s responsibilities across various intelligence disciplines, including analysis, collection, and security, along with the management of international intelligence relationships.