In this chapter we will explore eleven guidelines which we have developed in order to help us keep user-friendly concepts at the centre of our work. We have chosen to use the term ‘working guidelines’ to reflect the fact that we need to undertake a great deal of additional work in order to ensure that they actually perform their function. In the following sections of this chapter each guideline will be briefly stated before we attempt to summarize the experiences, research and theorizing that prompted its formulation.