This essay summarizes the theory and practice of computer simulation, assesses the state of the art of simulation with respect to pedagogically relevant processes like learning, and speculates about the impact of such simulations on pedagogical research and practice. Arguing that the use of computer simulation as a technique for building formal models of mental processes forces the cognitive psychologist to consider the content of strategic or heuristic knowledge, the paper begins by discussing such philosophical concepts as the formalization of theories, the distinction between theories and models, and the notion of a research program. The rationale and workmode of simulation research are then summarized, and a review of the literature illustrates the range of phenomena with educational relevance to which the simulation technique has been applied. The new connectionist approach to simulation is described, and concern is expressed about the way in which knowledge appears in connectionist theories. The most direct interaction of computer simulation with education in the future is predicted to be through such computerized teaching tools as intelligent tutoring systems and systems for automatic cognitive diagnosis. It is concluded that a traditional science-to-practice knowledge transfer will occur to the extent that simulation models contribute to the improvement of psychological theories with pedagogical relevance, and that computerized teaching devices will have a dramatic effect on cognitive research methodology by providing access to information on the behavior of students in real learning situations. A list of 170 references is provided. (MES)