Comprehensively reviews the current knowledge concerning neuroanatomy and neurochemistry as it relates to this part of the brain. In particular it explores the functions of this structure as well as its involvement in clinical conditions such as Alzheimer's disease, epilepsy and schizophrenia. Specific topics include anatomical organization, cell types and intrinsic connections, the role of the amygdala in conditioned fear and social behavior, and the neuropathology of the amygdala in aging and dementia.