The mind reader is Gerwin Schalk, a 39-year-old biomedical scientist and a leading expert on brain-computer interfaces at the New York State Department of Health’s Wads­worth Center at Albany Medical College. The 
Austrian-born Schalk, along with a handful of other researchers, is part of a $6.3 million U.S. Army project to establish the basic science required to build a thought helmet—a device that can detect and transmit the unspoken speech of soldiers, allowing them to communicate with one another silently.

As improbable as it sounds, synthetic telepathy, as the technology is called, is getting closer to battlefield reality. Within a decade Special Forces could creep into the caves of Tora Bora to snatch Al Qaeda operatives, communicating and coordinating without hand signals or whispered words. Or a platoon of infantrymen could telepathically call in a helicopter to whisk away their wounded in the midst of a deafening firefight, where intelligible speech would be impossible above the din of explosions.

For a look at the early stages of the technology, I pay a visit to a different sort of cave, Schalk’s bunkerlike office. Finding it is a workout. I hop in an elevator within shouting distance of the paranormal hubbub, then pass through a long, linoleum-floored hallway guarded by a pair of stern-faced sentries, and finally descend a cement stairwell to a subterranean warren of laboratories and offices.