In this book we have examined a very wide range of self assessment practices used in a variety of disciplines and pursuing a diversity of educational goals. In an important sense, these are all merely illustrations of the potential of self assessment: a potential which has still to be fully realised. The basic message of the book has been that self assessment must be seen as much as a learning activity as an assessment practice. It can be justified primarily by resort to arguments about its role in improving learning although it has a secondary role in assessment where, under suitable circumstances, it can be used as part of the formal assessment system. Assessment, in all its guises, contributes to learning and influences what students spend their time on. So any use of self assessment must consider its relationship to other activities in the course of which it is a part.