Suicide implies a direct connection between the deceased's intention, his self-destructive action, and his subsequent death. Uncertainty about the correct certification results when the victim's intention is ambivalent, with coexisting wishes both to live and to die, or when the self-destructive action is in itself inconclusive, or when death follows the action after a considerable delay. Investigations of 100 such cases are reported with illustrative examples. The present classification of deaths into natural, accident, homicide, and suicide obscures the fact that individuals may make a considerable contribution toward their own deaths under circumstances not ordinarily considered suicide.