After a death by suicide, the most troubling questions are the most difficult to answer, including the question of why. Drawing on clinical & epidemiological evidence as well as personal experience, Joiner found 3 factors that mark those most at risk of suicide: the feeling of being a burden on loved ones; a sense of isolation, & the learned ability to hurt oneself. The theory is tested against evidence taken from clinical anecdotes, history, literature, popular culture, anthropology, epidemiology, genetics, & neurobiology.