Assistive technology that helps severely paralyzed people navigate the world and communicate with others often taps into whatever abilities the disabled retain, such as blinking or moving the mouth and tongue. Now, for the first time, researchers have invented a device that allows the paralyzed to write, surf the Web and steer an electronic wheelchair--all by sniffing. Initial tests, described July 26 in Proceedings of the National Academy of Sciences ( PNAS ), suggest that many severely paralyzed people can easily master the "sniff controller," which offers certain advantages over other technological aids.