The basic science of diagnosis and treatment of mental illness is described from the point of view of the practitioner. My experience may be different from psychiatrists in public health, research, and academic settings. I have been at the point of service since 1970 as a medical student, since 1972 as an intern and since 1973 as a licensed medical doctor and since 1977 as a board-certified psychiatrist. The practice of psychiatry changes from place...