Abstract: An interactive training/expert computer system includes a computer subsystem for executing computer programs. A keyboard is used for entering data into the system, and a CRT displays the results of executing a computer program in the computer subsystem. A preselected computer program is resident in the computer subsystem. A tutor module interrupts the flow of data from the keyboard, interpreting and manipulating the input data, selectively generating messages in response to the input data, and selectively allowing a subset of the input data to be processed by the preselected computer program. The interpreting, manipulating, generating and allowing functions are dynamically determined in accordance with predefined criteria dependent on the contextual circumstances in the running of the preselected computer program.