Peter Tyrer is the Professor of Community Psychiatry in the Centre for Mental Health in the Division of Experimental Medicine, Imperial College, London, UK. His main interests are in models of delivering community psychiatric services, the classification and treatment of common mental illnesses, particularly anxiety and health anxiety, and the classification and management of personality disorders. He also leads on research into the management of patients with intellectual disability and on new psychological treatments for a common but largely unrecognised condition, health anxiety. He is experienced in the management of those with severe mental illness, substance misuse and personality disorder and has developed a new treatment, nidotherapy, to help these people by making environmental, not personal, changes. Much of his recent work has been concerned with improving and extending the concept of personality disorder. Personality disturbance is very common, not just in psychiatric practice, and this importance has been largely unrecognised as the classification system for this group of disorders is so poor. Fortunately, a major reform of classification is under way and will both simplify, and, we hope, destigmatise a very common form of mental distress.