This paper presents a critical review of computer assisted instruction (CAI); an overview of recent intelligent tutoring systems (ITSs), including current perceived shortcomings; major activities of the field, i.e., analysis of teaching/learning processes, and extending and developing artificial intelligence techniques for use in intelligent tutoring systems; and a methodology for building ITSs. Examples are given from recent work on a student modelling system used to develop an ITS for algebra. A research agenda for ITS development relating to current activities in artificial intelligence (AI) and cognitive science is suggested and a list of 36 references is provided. (MBR)