The brain has long been considered an immune privileged organ, meaning that inflammatory cells are excluded due to a relatively impenetrable blood brain barrier (BBB). However, this is not to say that the central nervous system is incapable of eliciting immune responses, as resident inflammatory cells exist within the brain parenchyma. Microglia have long been thought to be the brain's resident immune cell with myeloid lineage similar to monocytes and macrophages. In this volume, the authors review the current state of knowledge with regard to immune responses and cell-cell interactions as they pertain to a variety of neurodegenerative diseases. The changing role of inflammation with development is considered. They also present a summary of the various therapeutic strategies employed both in the laboratory and at the clinical level.