It was a common view among 19th century historians and clinicians that the study of delusions was the study of insanity itself (Ball & Ritti, 1881). At the beginning of the 20th century, Jaspers rendered this insight into a cliche (Jaspers, 1963). The nature of the link between delusion and insanity, however, has continued to confuse scholars, particularly those writing in the English language (Ireland, 1885; Arthur, 1964; Moor & Tucker, 1979; Winters & Neale, 1983). German (Huber & Gross, 1977), French (Ey, 1950) and Spanish (Cabaleiro Goas, 1966) writers have fared better; unfortunately, much of their work remains inaccessible to English-speaking psychiatrists. This is one of the reasons why, in Anglo-Saxon psychiatry, it has been suggested that the ‘definitive‘ view on delusions started with Jaspers and the Heidelberg school (Hoenig, 1968). This suggestion is misleading (Berrios, 1991), for by 1912, when Chaslin published his great work on descriptive psychopathology, all the distinctions nowadays attributed to Jaspers had already been made. Indeed, the rare efforts made to escape from the ‘pathological belief view were ignored (Southard, 1916).