The information presented here is on the incidence of suicide in the United States and in other countries where reporting procedures are reliable. The problem of underreporting is discussed and put into perspective. Secular trends in suicide incidence are presented, and it is shown how these have varied a great deal for different age groups. Age, ethnic, and cultural differences in incidence are demonstrated, and explanatory theories for these differences are put forward. The phenomenon of cluster suicide is described, and possible explanations for this are discussed. The limitations of death certificate data and the advantages (and limitations) of the psychological autopsy method are presented. Results from previous psychological autopsy studies on epidemiologically sound samples are summarized. Results (preliminary) from a current psychological autopsy study on consecutive adolescent suicides in the New York Metropolitan area are presented. Family history data and diagnostic profiles of completed suicides are emphasized.