Subarachnoid hemorrhage (SAH) can be classified as spontaneous or traumatic bleeding into the subarachnoid space. It is usually followed by a head injury or due to an aneurysmal rupture. Aneurysmal SAH is often a devastating occurrence that usually affects the younger population and is associated with high morbidity and mortality. Chronic smoking, heavy alcoholism, hypertension, atherosclerosis, late pregnancy are well-documented risk factors for subarachnoid hemorrhage. This book discusses the epidemiology, management and long-term health effects of subarachnoid hemorrhages.