The Kübler-Ross model, commonly known as the five stages of grief, is a theory first introduced by Elisabeth Kübler-Ross in her 1969 book, "On Death and Dying". Based on the uncredited earlier work of John Bowlby and Colin Murray-Parkes, Kübler-Ross actually applied the stages to persons who were dying, not persons who were grieving. Her studies involved her work with the terminally ill. The popular but empirically unsupported model describes in five distinct stages how people deal with their impending death.