This book focuses on the interplay between communication behavior and the body’s physiological processes. The first half of the text addresses basic anatomy and physiology of some of the body’s major systems, including the brain, the nervous system, the endocrine system, and the musculature system. In the second half, specific studies are reviewed that relate physiological processes to various communicative contexts, including love, conflict, sex, stress, emotion, parenting, and relational maintenance. Focus throughout the book is on the interaction between body and behavior: how physiology affects communication, and how communication, in turn, affects physiology.