The Diagnostic and Statistical Manual is the primary reference catalog for mental health illnesses. But whereas a medical textbook will show you the picture of a broken bone or a tumor, leaf through the DSM and you will find just one thing: lists of symptoms. Who creates these lists, and based on what criteria? Do such lists really capture the nature of a mental illness? What does it mean to be a disease of the mind versus a disease of the body? Does our classification system construct mental illness, or does it reveal underlying facts from genetics or neuroscience?