A short and accessible overview of current thinking on psychiatric disorders. As expected, this fourth edition concentrates on the standard classifications: the DSM (the American Psychiatric Association’s Diagnostic & Statistical Manual Diagnostic of Mental Disorders) and the ICD (the World Health Organization’s International Classification of Diseases), but it does take a bigger picture and, when talking about the upcoming 11th revision of ICD, is honest enough to say that the changes have taken place “against a background of concern about the validity of most of the categories in the classifications heretofore.”