High Quality Content by WIKIPEDIA articles! The Office of the Secretary of Defense (OSD) is a headquarters-level staff of the Department of Defense of the United States of America. It is the principal civilian staff element of the Secretary of Defense, and it assists the Secretary in carrying out authority, direction and control of the Department of Defense in the exercise of policy development, planning, resource management, fiscal, and program evaluation responsibilities. OSD includes the Immediate offices of the Secretary (SECDEF) and the Deputy Secretary of Defense (DEPSECDEF), as well as five Under Secretaries of Defense in the fields of Acquisition, Technology Logistics; Comptroller/Chief Financial Officer; Intelligence; Personnel Readiness; and Policy. All of these positions are Presidential appointments which require U.S. Senate confirmation.