Introduction

Writing good documentation is hard. Hardest of all, perhaps, is to write good user manuals for computer software. The reason why this is so difficult is that there is a great diversity of possible readers, and of modes of perusal. Readers will range from the naive to the expert, and in between there are important special cases of readers with expertise in a related area, such as a FORTRAN expert learning BASIC. Furthermore readers, whatever their background, will want to peruse the user manual in different ways at different stages in their learning process. Early on they will want summaries and tutorial information; later they may want to browse; finally they will want a reference manual. In order to cover this spectrum properly you need a huge range of user manuals. In a few spheres this range exists: there is, for example, a big range of manuals – mostly books – on Pascal and many of these are aimed at specific niches in the market of possible readers.