The Hoarders argues that the mental illness of hoarding (Hoarding Disorder) is not an individual pathology. While abnormal psychology and social work use classification systems such as Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) to legitimize the activity as a mental disorder, this book disputes these diagnoses. Examining how scientific research, the entertainment industry, the professional organizing industry, and others promote knowledge about hoarding, this book presents an extended cultural study of improper forms of collecting and unorthodox material culture in the modern United States. It also connects hoarding to social fears over urban disorder, proper housekeeping, and old age. To do so it offers four cultural biographies of things that established hoarding’s entry into DSM-5. These chapters each trace a different backstory of the disease. Collyer Brothers syndrome, Chapter 1 argues, advanced what experts refer to as chronic disorganization, a trait often considered a symptom of Hoarding Disorder. Chapter 2 reveals abnormal collecting to be a cornerstone of the DSM diagnostic. Chapter 3 does likewise for Messy House syndrome, Pack Rat syndrome, and fears over excessive clutter. Senile squalor syndrome, Chapter 4 details, established stereotypes of the elderly as aberrant hoarders. Together these accounts narrate how hoarding shifted from an eccentric engagement with ordinary things such as curios, clutter, keepsakes, and collectibles into a twenty-first century mental disease.