Kiss your keyboard goodbye: soon we'll jack our brains directly into the Net - and that's just the beginning. Two years ago, a quadriplegic man started playing video games using his brain as a controller. It spells the beginning of a radical change in how we interact with computers. Someday, keyboards and computer mice will be remembered only as medieval-style torture devices for the wrists. All work - emails, spreadsheets, and Google searches - will be performed by mind control. [Consider] the sensational research that's been done on the brain of one Matthew Nagle. Nagle, a 26-year-old quadriplegic, was hooked up to a computer via an implant smaller than an aspirin that sits on top of his brain and reads electrical patterns. He learned how to move a cursor around a screen, play simple games, control a robotic arm, and even...turn his brain into a TV remote control [all] in less time than the average PC owner spends installing Microsoft Windows. Neurodevices - medical devices that compensate for damage to the brain, nerves, and spinal column - are a $3.4 billion business that grew 21 percent last year. There are currently some 300 companies working in the field. This kind of technology can enable a hooked-up human to write at 15 words a minute. Remember, though, that silicon-based technology typically doubles in capacity every two years. Last year, Sony took out a patent on a game system that beams data directly into the mind without implants. It uses a pulsed ultrasonic signal that induces sensory experiences such as smells, sounds and images.