The early nineteenth century saw the emergence of institutional psychiatry across Europe. Aware that Sweden had fallen behind in this development, Parliament decreed in 1823 that a number of specialised institutions for the care of the insane were to be established. The Vadstena asylum, opened in 1826, was the first such institution in Sweden.   The aim of this study is to examine medical interpretation of and responses to erotic behaviour in psychiatric practice at the Vadstena asylum in the period 1849-1878. The book places the theme of the erotic, a topical subject in nineteenth-century public debate, in the context of psychiatry as an emerging specialty in Sweden. The book explores how erotic behaviour was conceptualised as disease, and the nature of therapeutic intervention in erotic cases, in order to present a more nuanced image of nineteenth-century medical attitudes to sexuality. By highlighting the superintendency of physician Ludvig Magnus Hjertstedt, and linking his account of an 1845 study tour through Europe to medical practice at Vadstena, the study situates responses to erotic patients in a period when psychiatry claims authority over human sexuality.   In methodological terms, the study applies critical questions inspired by revisionist scholarship to a body of empirical source material. Focusing on a single institution, and conducting in-depth readings of case notes – with regard to language, form, and function – allows the study to highlight the everyday practice of the asylum physician in his encounters with male and female erotic patients, including the use, importance and diagnostic integrity of the concepts nymphomania, erotomania and masturbation. Hjertstedt’s travel journal provides insight into the physician’s medical philosophy, informing the analysis of diagnostic and interpretive procedures, while connecting medical practice at Vadstena to its European paragons.     The results indicate that while the use of specific diagnostic terms to describe erotic behaviour was infrequent, therapeutic and managerial intervention shows that sexual acts and expressions of desire were considered disturbing and dangerous symptoms in both male and female patients. The analysis thus makes visible a gap between psychiatric theory and asylum practice, emphasising uncertainties and complexities inherent in the latter. While erotic behaviour could be considered indicative of illness, it might also be interpreted as a lack of character or a result of insufficient moral instruction. The asylum’s regime of work and moral instruction was designed to restore health as well as sound values and appropriate behaviour in its patients, indicating a medical culture at Vadstena which was both curative and normalising.