I often surprise people with the simple fact that your cell phone today has more computer power than all of NASA when it put two men on the moon in 1969. Computers are now powerful enough to record the electrical signals emanating from the brain and partially decode them into a familiar digital language. This makes it possible for the brain to directly interface with computers to control any object around it. The fast-growing field is called BMI (brain-machine interface), and the key technology is the computer.