Throughout the ages, sudden unpredictable loss of consciousness has plagued patients and frustrated and fascinated physicians. Hippocrates is credited with having made the first description of syncope; the medical term for fainting is derived from the Greek term syncoptein (to cut short). Recurrent syncope may be a sign or a symptom and may occur as a result of a wide variety of different causes. In the 1990s, a substantial amount of research was devoted to syncope resulting from sudden periods of centrally mediated hypotension, a phenomenon initially referred to as vasovagal syncope. Extensive investigations into the nature of this disorder soon uncovered that it represents only one aspect of a broad, heterogeneous group of disturbances of the autonomic nervous system that can result in hypotension, orthostatic intolerance, and often syncope. This flood of new information has caused investigators to reassess the classification of autonomic disorders and to develop the current level of understanding. The new system of classification attempts to be practical and useful clinically (however, any such attempt at classifying natural phenomena has its limitations). This article provides a brief overview of these disorders, their pathophysiology, and management.