By one estimate, between fiscal years 1995 and 2005, total compensation costs for current and former military personnel increased by almost 60 percent. The military retirement benefit remains a significant portion of these costs, and every change to accessions, retention, and basic pay today will have a future effect on pension expenditures. This technical report provides an overview of the history of U.S. military retirement studies and associated legislation, with a particular focus on the past 60 years of proposed reforms. It is organized around the following five major issues that have driven attempts at retirement system reform: cost, equity, selective retention, civilian comparability, and force management flexibility. The author finds that cost alone is reason to analyze the current retirement system, and reform proposals of the past have focused carefully on cost. However, he also finds that, as the military's mission evolves over time, it is also important to consider the sometimes subtle incentive effects that the retirement system has on service member behavior. Beyond considerations of cost, reform of the military retirement system necessarily involves ramifications for force structure and operational readiness.