Suicide is currently the 11th leading cause of death in the United States and is a major global health concern that encompasses biological, psychological, and social factors. Although suicide has a long history of existence, suicide trends in the United States have significantly changed within the past century. The trend analysis shows a significant increase in male and female suicide rates during the second and third decades of life; the highest suicide rate throughout the 20th century was noted for Caucasian males and increased with age. The last decade of the 20th century witnessed a 14 percent decrease in the national suicide rate. Trends in the method of suicide are examined; the analysis shows that since 1910, the primary method of suicide has been death by firearms. Risk factors affecting suicide are described, as are the mental illnesses most frequently linked to an increased risk of suicide (major affective disorder, schizophrenia, and neuropsychological sequelae of chronic alcoholism). The forensic investigation of suicide should include an extensive scene investigation and a thorough postmortem examination with complete toxicological study. The psychodynamics of the suicide autopsy are reviewed and an international perspective on suicide is offered. Tables, figures, references