The Assistant Secretary of Defense for Sustainment, formerly known as the Assistant Secretary of Defense for Logistics and Materiel Readiness, is one of three assistant secretaries reporting to the Under Secretary of Defense for Acquisition and Sustainment. Formerly the position was an adviser to the Under Secretary of Defense for Acquisition, Technology and Logistics, Deputy Secretary of Defense, and Secretary of Defense on logistics and materiel readiness issues within the Department of Defense (DoD), including programs related to logistics, materiel readiness, maintenance, strategic mobility, and sustainment support. As the principal logistics official within the senior management of the DoD, the ASD (L&MR) exercises authority, direction and control over the director of the Defense Logistics Agency. Like all other Assistant Secretaries of Defense, the ASD (L&MR) is considered a part of the Office of the Secretary of Defense. As part of a reorganization on 1 February 2018, the ASD(L&MR) was abolished and combined into a new Assistant Secretary of Defense for Sustainment.