The kindling model of epilepsy was discovered relatively recently (Goddard et al., 1969), yet it is already the most extensively studied animal model of epilepsy. Despite extensive study, the mechanisms responsible for kindling are unknown. Our intent in this chapter is: 1) to identify some difficulties confronting investigations of the mechanisms; 2) to describe our studies of the substantia nigra in kindling; and 3) to consider how these studies of the substantia nigra may contribute to understanding the mechanisms of kindling.