Mental illness overwhelms its millions of victims with a variety of disabling symptoms, including extreme fearfulness, depression, and inability to distinguish the imagined from the real. In the late 19th century many psychiatrists, including the young Sigmund Freud, were convinced these disorders were biological in origin. But when Freud concluded that the knowledge and methods of that time were too limited to attack the complex problems of mental illness, he turned his attention to exploring its psychological aspects, setting a course that psychiatry would follow for many decades. Today, supported by the huge growth of molecular, genetic, and cellular research, the biological approach to psychiatry is making tremendous strides. As a result, we are poised to achieve significant new levels of success in alleviating the suffering of the mentally ill. In this volume the author describes the crucial role biological research is playing in modern psychiatry. The book explains the essential principles of human genetics, molecular biology, neuroscience and psychopharmacology that are helping scientists and practitioners understand the biological roots of mental illness.