Estrogen and testosterone have an important impact on the operation of certain parts of the brain. This book describes the neurobiological bases for the understanding of the interactions between these sex hormones and the brain. It covers a broad range of topics, extending from the molecular and cellular processes, through the action of steroids on neurotransmission, all the way to defining the brain circuitry involved in both male and female behavior. This volume presents a snapshot of the rapidly advancing field of reproductive neuroendocrinology and will be an important resource for graduate students and professionals in neuroscience and animal behavior.