Coma is an ominous sign and has been known since antiquity. Over several decades, a much better understanding of the mechanisms of coma, patterns of brain tissue shift, and its clinical correlates has developed. Methods of the examination and the details of approaching a diagnosis of patients in coma have evolved gradually over this time. In this chapter, the key articles that formed the basis of this evaluation are discussed. These articles offer an understanding of how the current level of sophistication regarding determination of the severity of brain injury, of improvement potential, and of an appropriate level of care was reached.