SIMNET stands for SIMulator NETworking. Initiated in 1983, it was the first “shared virtual reality� distributed simulation system, which continues to have significant influences. It was sponsored by DARPA, the Defense Advanced Research Projects Agency, the Department of Defense’s principal high-risk, high-payoff research and development organization, established in 1958. In 1991, a study of various DARPA initiatives by the Potomac Institute for Policy Studies listed SIMNET as one of six programs that have had the most profound effects on the DoD. To put this in perspective, the other five were the ARPANET (the predecessor of the Internet); the individual computer workstation; phased array radar; the stealth technology used to make aircraft such as the F-117 fighter and the B-2 bomber “invisible� on radar; and ATACMS, the low cost, long-range tactical artillery rocket system used successfully in Desert Storm to destroy enemy surface-to-air missile sites and other targets (Potomac Institute for Policy Studies, 1991). That’s quite a distinguished list in which to be included!