Revised and updated throughout, the third edition includes enhanced discussions of the distinction between mental health and illness, selfhood and delusions about the self, impairments of basic psychological capacities in mental disorder, and the distinct roles that mental causation and neural mechanisms play in mental illness. The book is organized around four questions: • What is a mental disorder or illness? • What makes mental disorder something bad? • What are various mental disorders and what do they tell us about the mind? • What is mental health and how may it be restored? Numerous disorders are discussed, including addiction, agoraphobia, delusion, depression, dissociative identity disorder, obsession-compulsion, schizophrenia, and religious scrupulosity, among others. Several neurological disorders are examined. Various problems associated with DSM-5 and with psychiatric diagnosis are explored. Including chapter summaries and suggestions for further reading, is an ideal text for courses in philosophy and should appeal to not just philosophers, but to readers in cognitive science, psychology, psychiatry, and related mental health professions.