Defense Primer: Under Secretary of Defense for Research and Engineering [February 21, 2018] [open pdf - 447KB]
From the Document: "Advances in science and technology have long played a critical role in ensuring the technological preeminence of the United States military. For this reason, the Department of Defense (DOD) is the largest funder of federal research and development. The Under Secretary of Defense for Research and Engineering (USD(R&E)) is a civilian official reporting directly to the Secretary of Defense. The USD(R&E) serves as the principal advisor to the Secretary of Defense for DOD research, engineering, and technology development activities and programs."
CRS In Focus, IF10834