periodically into the "Stealth Room." "Stealth technology" cloaks observers in digital invisibility, so that they can travel to any point inside a simulated battle. A huge triptych of full-color computer screens showed the simulated activity of a certain weapons system I was forbidden to identify publicly. The tarpaulin-shrouded chambers within the Institute were draped with wrist-thick clusters of black cabling leading to Sun workstations, networked Macintoshes, and a variety of prototype simulators. Everything hummed.

Col. Jack A. Thorpe, USAF, Ph.D., spends a lot of time in the Institute. Col. Thorpe is the "Father of Distributed Simulation" and is America's foremost advocate of virtual reality as a strategic asset.

The Colonel wore a civilian pinstriped suit, an understated maroon tie, and polished black wingtips. Col. (or Doctor) Thorpe is a cognitive psychologist specializing in training techniques; he is tall and lean and bespectacled, with a straight nose, dark hair, and hollow temples, and he possesses the vigorous air of a man with a vision and clear ideas of how to get there. He is somewhere near his early forties.

Col. Thorpe's highly unusual expertise makes his position in the military hierarchy somewhat anomalous. He is a career Air Force officer who nevertheless pioneered virtual reality networks for the US Army. He is also the special assistant for simulations at DARPA. He clearly has a lot of pull at the Institute for Defense Analyses, his institutional home away from home, where DARPA sponsors the IDA Advanced Distributed Simulation Laboratory.

Col. Thorpe also has a number of friends among the computer-networking experts at the University of Central Florida in Orlando, and more colleagues yet at the Defense Mapping Agency, and yet more in the Topographic Engineering Center, and plenty of eager listeners from all over the defense-contracting industry.