We believe that the outline of a promising approach to the study of expert clinical problem-solving is emerging. This process involves collecting as verbal transcripts the thoughts of experienced clinicians engaged in simulated clinical tasks and analyzing these transcripts to formulate theories of problem-solving tactics and strategies. In turn, these theories are embodied in a computer program that simulates the problem-solving process. The computer program's response to fresh clinical problems can be compared with physician behavior in order to revise, refute, or confirm the problem-solving theories. A scientific understanding of the expert clinician's reasoning strategies could prove exceptionally useful in improving the way we teach and practice medicine and in developing practical computer aids for medical decision-making.