So far, the chapters in this book have explored how, in clinical psychiatry, the notion of insight has become conceptualised as an independent phenomenon, one that not only could be observed (to different extents) in patients with mental illness but one that could, moreover, be measured and related to other clinical and non-clinical variables. We have seen how, in Western cultures, this demarcation of insight as an independent variable became possible in the context of a number of factors including, a background of philosophical/psychological thought encouraging self-observation and self-understanding, changing ideas concerning the nature of mental illness itself, and, an environment that fostered close clinical observation. Then, reviewing the study of patients' insight in various clinical areas, we have seen that perspectives taken to understand and assess insight in clinical (and non-clinical) populations have been quite different. In part, this seems to have occurred as a result of diverse theoretical positions taken by the different professional disciplines. In addition, however, and closely interlinked with this is the fact that the different demands of the various clinical populations have determined to some extent the approaches taken. This issue will be discussed in more detail later. However, it is of interest to reiterate, that in general psychiatry it was the observation that patients with mental illness could have insight that led to further work exploring this phenomenon. In contrast, in patients with neurological/neuropsychological impairments, it was the converse observation that determined approaches exploring insight in this clinical group.