ABSTRACT
Throughout the process of writing a field guide, decisions on, for example, content, the type of illustrations and keys will have been taken with representatives of the end users and balanced against the resources available. Such activities reduce the possibility that a guide will be unacceptable and incomprehensible. However, the ultimate test of the guide is not only that it contains useful information, presented in a format that people like and understand, but that it is usable for the kinds of tasks which people want to perform. Chapters 5 to 8 have all pointed out the need to both pre-select formats in consultation with users, and to test the chosen formats at an early stage to ensure that they are understood by the users.
