This article is a commentary on “A Definition of Irreversible Coma”, originally published in JAMA 1968;205(6):227-340 Commenting on the seminal 1968 paper defining criteria for determining brain death, Dr. Rosenberg emphasized the staying power of these criteria and explains new understandings of neurological states often confused with brain death, such as persistent vegetative state (PVS) and coma. The review proved a patient could have a dead brain in an otherwise healthy body and the identified this state as irreversible, both key steps in allowing for organ donation from these patients. Brain death is determined by the absence of all reflexes and normal brain electrical activity. PVS and coma patients, in contrast to brain dead patients, demonstrated neurological activity without visible wakefulness. These findings suggest that future research could elucidate what is happening in these states. Forty years after the Harvard paper, the concept of brain death and the road it paved to organ donation is strong; much work is left to be done to understand similar neurological states such as PVS and coma.