The software has been developed in Smalltalk80 1] on SUN and Apple Macintosh computers. Smalltalk80 is an object-oriented programming system which permits rapid prototyping. The need for prototyping in the specification of general practitioner systems was highlighted as long ago as 1980 4] and is essential to the user -centred philosophy of the project. The goal is a hardware independent system usable on any equipment capable of supporting an integrated environment for handling both textual and graphics and 'point and select' interaction. The architecture is extensible and provides a...