DESIGN: Clinical issues to be addressed will include disease manifestations, natural history, acute disease management, and psychological/behavioral impact of the disease. Because of the nature of acute cerebrovascular disease, it is important to note that the research performed under this protocol will not interfere with emergency clinical evaluation or treatment of subjects, as specified in the clinical care pathway in place for the standard care of stroke patients at participating hospitals. Due to the emergency nature of clinical evaluation and therapy for stroke patients, waiver of written informed consent in certain circumstances for minimal risk procedures during acute period (e.g., collecting extra tubes of blood during initial phlebotomy for emergency room blood tests) will be required when it is impossible to obtain consent prior to critical emergency treatment procedures that may change the values of the variables. Patients will not be treated with experimental therapies as part of this protocol. Data collected under this protocol may be shared with other NIH researchers and databases and the National Institutes of Neurological Disorders and Stroke (NINDS) Repository if the subject approves this option in the informed consent.