Against a backdrop of contemporary social and sexual concerns, and potent fears surrounding the moral and physical 'degeneration' of late nineteenth and early twentieth-century society, 'The Cruel Madness of Love' explores a critical period in the developing relationship between syphilis and insanity. General paralysis of the insane (GPI), the most commonly diagnosed of the neurosyphilitic disorders, has been devastating both in terms of its severity and incidence. Using the rich laboratory and asylum records of lowland Scotland as a case study, Gayle Davis examines the evolution of GPI as a disease category from a variety of perspectives: social, medical, and pathological. Through exploring case notes and the impact of new diagnostic techniques and therapies, such as the Wassermann Test and Malarial Therapy, the reader gains a unique insight into both patients and practitioners. Significant insights are gained into the socio-sexual background and medical experience of patients, as well as the clinical ideas and judgmental behaviour of the practitioners confronting this disease. 'The Cruel Madness of Love' will be of interest to anyone wishing to explore the historical relationship between sexuality, morality and disease. Gayle Davis is a Wellcome Trust University Award Holder at the University of Edinburgh. She has published on various aspects of the social history of medicine and sexuality in twentieth-century Britain, and is undertaking a Wellcome-funded research project on the history of infertility in Scotland. She is reviews editor for History of Psychiatry.