Elizabeth Kübler-Ross (1926-2004) was one of the first thanatologists to publish a stage theory about the grieving process. Her work was based on studies of the terminally ill. While her model has been criticized, her descriptions of the five stages of grief are still highly influential and provide a good overview of the variety of emotional experiences people undergo while grieving. The five stages of grief are as follows: denial, anger, bargaining, depression, and acceptance.

The first stage is denial. When people first learn of their terminal illness, they go into shock and try to deny that it is real. The next stage involves anger. People learning of their own impending death are frequently angry. This anger may be expressed at doctors, at family, or even at themselves. It is as though they are looking for a place to put their anger at their illness. The next stage involves bargaining. They try to bargain with doctors, friends, family, and even God. By holding onto the belief that they can change the outcome of their illness through “good” behavior, they try to maintain a sense of control. When the reality of death finally sinks in, the result is depression. Ultimately, the person absorbs the intense and devastating shock of their terminal illness. At this point, they reach the stage of acceptance, in which they can face death with a degree of resolution and psychological peace. Later research has shown that not all dying patients go through each stage, nor do they go through them in the same sequence. Nonetheless, many people do experience the states of mind that Kübler-Ross describes.