This text asserts that a stroke should be thought of as a syndrome, or collection of disease processes, rather than a single disease. Strokes are characterized by restriction of blood flow to the brain and are responsible for imposing a very significant burden on healthcare systems, accounting for more than four million deaths per year. They can be directly linked to the majority of adult neurological disability and they contribute to vascular dementia, the second most common cause of dementia after Alzheimer's Disease. Despite its importance on a population basis, research into the genetics of strokes has lagged behind many other disorders; however, the situation is changing and there is now growing evidence that genetic factors are important in the stroke risk, often acting via interactions with conventional risk factors.