Epilepsy is a neurological condition that is characterized by recurring, unprovoked seizures. Epilepsy can be caused by a genetic mutation or by a neurological insult such as a stroke or traumatic brain injury. Most commonly, though, the cause of epilepsy is unknown. The most recent reports estimate that 4.3 million adults and 750,000 children have a diagnosis of epilepsy with epilepsy being the most common childhood neurological disorder in the United States. This entry details the various classifications of epilepsy, diagnosis and treatment, and the impact of epilepsy on speech and language development.