The knowledge base for treating elderly persons with epilepsy is limited. There are few known knowns, many known unknowns, and probably many unknown knowns, that is, the things we know that "ain't so." We know that the incidence and prevalence of epilepsy is higher in the elderly than any other age group, that the elderly are not a homogeneous group, that epilepsy is much more common in the nursing home population than in the community-dwelling elderly, and that antiepileptic drug (AED) use varies greatly among countries, but that in all, the older AEDs (phenytoin, phenobarbital, and carbamazepine) are the most commonly used. We also know that drugs that require hepatic metabolism for elimination are subject to pharmacokinetic changes with age and may be problematic because of drug-drug interactions. There are many known unknowns in both the basic science of brain aging and the susceptibility to epilepsy, and many clinical issues remain unresolved. Some unknown knowns (i.e., misconceptions) are that the elderly need levels of AEDs similar to those for younger adults and that AED levels do not fluctuate widely. This book is designed to help the reader understand the issues and, hopefully, to stimulate research to provide answers for the known unknowns.