This chapter focuses on human self-destructive behavior. Human self-destructive behavior has many determinants. In considering animal models for human behavior one cannot propose that similar behaviors necessarily have the same causation in human beings. Even if environmental conditions or the resulting behaviors vary for different species, the biochemical intermediaries may be similar. The ethological aspect of such discussion may help to place human self-destructive behavior in a continuum with that of animals drawing direct parallels may be out of place but we can conclude that humans are not alone in exhibiting self-initiated behaviors that produce self-harm or death. This chapter covers the historical, religious, philosophical and cultural background, meanings of suicide, classification of suicide, epidemiological approach, sociofamilial approach, psychological approach, psychiatric approach, biological aspects of suicidal behavior, suicidal behavior in special groups, indirect suicidal behavior, and methods in suicidology.