Suicide is a serious problem, hallmarked by complexity and ranked as a leading cause of death worldwide. International studies of suicide epidemiology show that suicide rates are generally greater in males than females and increase with age, with the elderly having the highest suicide rates (WHO, 2002). The prevention of suicide is, in part, contingent on the ability to identify individuals and populations at high risk and to offer prompt, effective interventions. However, evidence exists that suicidal individuals remain commonly undetected, rendering appropriate intervention unlikely. This encyclopedia presents important research on suicide.