user of IQ explores a computer laboratory in quantum mechanics gaining experience in this abstract field by performing computer experiments. No knowledge of computer programming is required. The user only has to learn how to use some ofthe simple IQ commands and, in particular, the exten­ sive HELP facilities. A simpler way to use IQ is to study one or several of the ready-made demonstrations. In each demonstration the user is taken through one chapter of quantum mechanics. Short explanatory texts displayed on the screen interchange with graphics illustrating quantum-mechanical problems which are solved by the program.