Elisabeth Kübler-Ross's book On Death and Dying introduced her now popular "stages of dying" which patients approaching death are said to experience. These steps do not necessarily come in order, nor are they all experienced by all patients, though she stated a person will always experience at least two. They are as follows:

1) Denial
2) Anger
3) Bargaining (patient tries, through will power or otherwise, to "earn" longer life - for example, by promising [perhaps to a higher power] to "be good")
4) Depression
5) Acceptance

The theory claims as well that survivors of the loss of a loved one will experience some combination of these stages over time, usually after that person's death. She also believed that to a lesser extent, a person may experience these stages as a reaction to any loss, for instance from divorce.

Critics accuse the Kübler-Ross model of being too simplistic, as human emotion is a complicated and varying thing. The model also has no application to most people approaching death, only those aware of their fate - terminally ill patients, for example.