Several studies suggest that idiopathic generalized or focal epilepsies can adversely affect mental development, cognition and behavior. Epileptic patients may experience reduced intelligence, attention, problems in memory, language and frontal executive functions. The exact mechanisms of epilepsy-related cognitive dysfunction are poorly understood. Cognitive deficits with epilepsy may be transient, persistent or progressive. Also antiepileptic drugs (AEDs) have differential, reversible and sometimes cumulative cognitive adverse consequences. This book serves as an overview of recent studies in cognition in adult and children patients with epilepsy. This book also discusses the known adverse mechanisms of epilepsy and AEDs on cognition.