This chapter explores a set of debates over the classification of mental disorder that occurred between 1902 and 1907 that were caused by attempts to revise and update the Table of the Forms of Mental Disorder. It explains how these efforts to revise the classification were set against a background of therapeutic nihilism that had fuelled an increased desire to link prognosis to diagnosis to prevent unnecessary admissions. It outlines how these revisions, published in 1907, led to changes in the ways that the data on psychological diagnosis amongst asylum admissions was collected, largely due to the introduction of a medical register that incorporated the Table of the Forms. The publication of the Table also played a significant role in the circulation of Kraepelinian concepts of mental disorder in the United Kingdom, principally because of the inclusion of the relatively novel concept of dementia praecox, reformulated as primary dementia for British physicians by those responsible for the revisions. Kraepelin’s work appealed to some involved in these debates because it catered for the desire for accurate prognosis amongst asylum medical superintendents who by the end of the nineteenth century were seeing burgeoning patient populations and drops in discharges that left institutions increasingly overcrowded. The 1907 Revisions signify the clearest moment when diagnostic categories that followed the classical division of madness, used for much of heyday of the asylum, were abandoned as the main categories for diagnosis. In outlining the debates and the eventual publication of the MPA’s 1907 Revision, this chapter argues that the classification that was a product of the revisions is a Kraepelinian document, and signals a turn towards Kraepelinian diagnosis used within asylum administration and mental health statistics.