The following epidemiological studies of cerebrovascular disease will be conducted under this grant: 1. Study of relationship of Stroke, Coronary Heart Disease and Hypertension; 2. A Community Study of Stroke in Washington County, Maryland; 3. Socioeconomic Status and Rates of Death Due to Stroke in Baltimore, Maryland 1969-1971; 4. A Study of Factors Influencing Survival After Stroke; 5. Study of Factors Associated with Elevated Blood Pressure; 6. The Relationship of Cerebrovascular Disease Mortality and Drinking Water at Home; 7. The Relationship of Myocardial Infarction to the Subsequent Development of Stroke; 8. Evaluation of the Use of the Logistic Function for the Analysis of Prospective and Survivorship Studies.