The authors have designed a user interface for the display and manipulation of radiographic images that is intended for use in digitized teaching files and computer-aided instruction (CAl) applications. By making the way the viewer interacts with a set of digitized images on the computer screen as similar as possible to the interaction with conventional films on a viewbox the authors have tried to create a system that combines the directness of the conventional teaching file with the power and flexibility of CAl. This is accomplished on readily available personal computer workstations.