Abstract: Military personnel costs, including health care costs, are substantial, amounting to more than $226 billion in the U.S. Department of Defense's (DoD's) budget request for fiscal year 2023. A major contributor to these costs, over and above the size and seniority of the force, is military compensation, which includes basic pay, allowances, special and incentive pays, retired pay, quality of life initiatives, and health care for military families and retirees. While some inefficiencies identified by past research have persisted for decades, the end of operations in Iraq and Afghanistan, emerging personnel requirements, and concerns about recruiting have renewed interest in how the compensation system could be improved. This report, produced prior to the work of the 14th Quadrennial Review of Military Compensation, summarizes the body of literature on military compensation, with the goal of identifying ways to improve efficiency and gaps in knowledge for which future analysis would be promising.