About four or five years ago one began to hear about the enormous interest being taken in on-line consoles and displays. Nothing much was done with them, but computer men felt that this was the way computing ought to go: one might dispense with cards, and overcome many of the problems of man-machine communication. It quickly appeared that, as with computers, there had been a great under- estimation of the amount of work involved, of the difficulties of programming, and of the cost. So it began to emerge that graphics was not the ultimate answer, in spite of superb demonstrations where one...