In our view, melancholia is a distinctive syndrome clinically defined by specific and pervasive disturbances in affect, psychomotor activity, vegetative functions, and cognition— and, in a subset of patients, by psychosis. The risk of suicide is high. Tricyclic antidepressants and ECT are differentially superior treatments. To advance diagnosis-specific treatment and research, melancholia should be acknowledged as an entity, not marginalized as a secondary specifier. Given the stakes, the importance of getting the diagnosis right is considerable.