"Hypertext" applications have become an important educational resource for medical teaching. ToolBook version 1.5 allows the import of SVGA 256 color, 640 x 480 pixel images. We developed a program for the review of Gastroenterology by Subspecialty Board applicants which included digitized pathology, endoscopy, dermatology, and radiology images interfaced with textual description. 5 cases were presented with 6 questions per case to test the user's comprehension of the material. A scoring function was included to give feedback to the users. An evaluation questionnaire was also completed to survey user satisfaction with the program. A similar "shell" could be applied to other teaching programs.