Genetic studies of the epilepsies are essential for clinical diagnosis, family counselling and as a critical route to understanding the basic biology of epilepsies at a molecular level. The focal epilepsies have been traditionally regarded as predominantly acquired disorders. This perception has now changed and there has been an explosion of interest in inherited forms of focal epilepsy that are emerging as being surprisingly common. This book describes the clinical features of the enlarging group of familial focal epilepsies and highlights recent molecular biological knowledge in understanding these disorders.