Death is defined as the cessation of all vital functions of the body including the heartbeat, brain activity (including the brain stem), and breathing. Death comes in many forms, whether it is expected after a diagnosis of terminal illness or an unexpected accident or medical condition.

As of 2001, the two leading causes of death for both men and women in the United States were heart disease and cancer. Accidental death was a distant third followed by stroke, chronic lung disorders, pneumonia, suicide, cirrhosis, diabetes mellitus, and murder. The order of these causes of death varies among persons of different age, ethnicity, and gender.

In an age of organ transplantation, identifying the moment of death may now have ramifications that involve another life. Its definition thereby takes on supreme legal importance. It is largely due to the need for transplant organs that death has been...