Life is a mysterious phenomenon, and so is death. Clini­- cal death is now defined as the permanent and irreversible ces­- sation of function of any one of the three interconnected vital sys­- tems, viz. nervous system, circulatory system and respiratory sys­- tem. Even after a person is no longer alive, individual cells and tissues remain viable for variable periods of time, making their transplantation possible. Physiologically, death represents fail­ ure of the homeostatic mechanisms. Cell death by necrosis as well as apoptosis is a regular phenomenon, but the organism continues to be alive due to replacement of cells. However, a point is peached when replacement and physiological reserve are un­ able to compensate for deterioration due to aging. Impairment of function beyond a point in one or more vital organs results in the death of the whole organism. The Mother (of Sri Aurobindo Ashram) described death as the “decentralization and disper­- sion of cells”. At the mental level, the replacement of the ‘will to live’ by a ‘wish to die’ is probably the beginning of decentraliza­- tion. Decentralization is followed by ill-health, and finally death. Following death, dispersion of cells possibly transmits their con­- sciousness to the new forms they assume. On the purely material plane, the time of death is inexorably fixed. But on higher planes of consciousness, a different type of determinism prevails. That is why the will to live, or its absence, may have a role in determin­- ing the time of death. Psychoneuroimmunology provides some partial but plausible explanations for the phenomenon. Death is both a physiological and a spiritual necessity. Physiologically, death is nature’s solution for the imperfection of the body. When the body has exhausted its functional span, it is withdrawn, usu­- ally only after it has renewed itself by reproduction. Thus the old order keeps yielding to the new. Death is also a spiritual neces­- sity because the true purpose of life is spiritual growth. When a person reaches the upper limit of his spiritual growth, further pro­- longation of life becomes meaningless.