This book includes questions of the etiology and morphogenesis of cerebral aneurysms, pathophysiological and pathomorphological aspects of subarachnoid hemorrhage and cerebral vasospasm, the relationship between constitution and developmental risk of subarachnoid hemorrhage, hemostasiological disorders in patients with aneurysmal subarachnoid and intracranial hemorrhage, peculiarities of diagnosis and methods of conservative and neurosurgical treatment in different types of patients with subarachnoid hemorrhage - adults, pregnant women and children. Anesthetic management of cerebral aneurysm surgery is an important topic of discussion. A special chapter is devoted to the analysis of the COVID-19 pandemic's influence on the dynamic of subarachnoid hemorrhage incidence as a neurovascular emergency. Finally, a very interesting chapter regarding the concerns, developments, and future direction of aneurysmal subarachnoid hemorrhage management is included. This book was written by neurologists, neuroradiologists, neurosurgeons, anesthesiologists and intensive care specialists, pathologists, laboratory diagnosticians and hemostasiologists - 23 authors from 4 countries, whose daily work is to manage and treat emergency vascular neurosurgical patients.