Many of the known degenerative syndromes that occur in situations where immune and neural cells die prematurely - resulting in disorders that involve both the nervous and the immune systems -, are termed neuroimmunodegeneration (NID) syndromes. This book addresses the intrinsic relationship between the nervous and immune systems, defines the NID syndromes and presents several examples of human and animal models for them. The advances in transgenic technology as new tools for investigating the specific features involved in pathogenesis are also discussed.