The new third edition of An Introduction to Behavioral Endocrinology retains all of the features of the bestselling prior editions, and provides an updated, integrated presentation of the study of hormone-behavior interactions. Continuing to emphasize a comparative approach, the text explores the endocrine mechanisms that have evolved in both human and nonhuman animals to solve common problems in survival and reproduction. The text describes hormone-behavior interactions from a historical perspective, emphasizing connections among key theories and tracing the emergence of important hypotheses. The book is organized around the conceptual theme that hormones may affect behavior by influencing one or more of three "components" of behaving animals: input mechanisms, such as sensory or perceptual processes; the central processing mechanisms of the nervous system (either directly, or by affecting its development or structure); and output mechanisms, such as effectors or peripheral structures. Despite increased coverage of molecular and cellular approaches, the book retains its accessibility for non-biological science students. An Introduction to Behavioral Endocrinology, Third Edition is appropriate for upper-level undergraduate and graduate courses in psychology, biology, anthropology, or zoology. It contains several important pedagogical features. The text is richly illustrated with photographs and drawings. Key terms are identified and defined in the text, and summaries at the end of each chapter restate important points. Discussion questions and suggested further readings are also included in each chapter. The text contains over 2,000 references to the literature in behavioral endocrinology.