This volume is composed of six sections, each addressing a different aspect of coping with the environment. Part 1 reviews the primary mediators of the coping response, including the adrenal medullary hormones, the sympathetic nervous system, catecholamines in the brain and responses to stress, the biochemistry and cell biology of corticotropin, proopiomelanocortin synthesis and cell-specific processing, and regulation and actions of the corticotropin-releasing hormone.