A robust modeling and simulation (M&S) capability enables the Department to more effectively meet its operational and support objectives across the diverse activities of the services, combatant commands, and agencies. A defense-wide M&S management process encourages collaboration and facilitates the sharing of data across DoD components, while promoting interactions between DoD and other government agencies, international partners, industry, and academia. This briefing takes a look at how DoD's vision of M&S and its place in the military has changed from 1996 to 2008. It then looks ahead to 2020.