The first computer made that used a monitor was the Alto, which was made by researchers employed by Xerox. Although the Alto was never sold for personal use, the Computer History Museum lists it as the first fully functional work station computer.
Although the Alto was the first computer made to work with a monitor, earlier computers made use of television screens as monitors. The TV typewriter, invented by Don Lancaster in 1973, was the first computer to send alphanumeric information to a separate screen and could be connected with a simple television set. Information on the screen could then be stored on a 90-minute cassette tape.