If ever there were a preface that ought to start with the words ‘Why another book on …’, this is probably it. Thought disorder is the most studied symptom of a much-studied disorder, schizophrenia, and there has been a long tradition of punctuating the steady stream of publications on the subject with books. There may be some justification for continuing this tradition, in that the last single-author book on the topic was written in 1990, and, while there have been one or two multi-author volumes since then, it is fair to say that neither of these caught the tide of two major developments in the field. One of these was the wave of clinical studies that followed the introduction of Andreasen's rating scale for what she called thought, language and communication disorders; the second has been the rise of the neuropsychological approach to schizophrenia.

Naturally, neither of these developments was the reason for writing this particular book, which had more maculate origins. It grew out of our attempts to get a paper based on the research in a Ph.D. published. After engaging in the usual titanic struggle with the reviewers, one of us said to the other in a flash of exasperation that the only way we would ever get the damn thing into print was by writing a book on thought disorder and putting the paper in it somewhere.