The Department of Defense (DOD) and the military services have taken steps to implement Product Support Managers (PSM) for major weapon systems, but certain aspects of the implementation process remain incomplete. The services have assigned PSMs to almost all of their major weapon systems. This book examines the steps, if any, that DOD and the military services have taken to implement PSMs for major weapon systems and the extent to which DOD has evaluated the effects, if any, that PSMs are having on life-cycle sustainment decisions for their assigned systems.