In this book, the authors present current research in the study of hormones and behavior. Topics include the neuroendocrine regulation of sedation and excitation in neonatal chicks; the behavior of the mother and vasopressin; inhibited TRHergic pathway of amygdala and insular cortex may participate in high anxiety levels and decreased food intake of dehydrated-induced anorexic rats; the difference between morning and evening thyrotropin response to protirelin(TRH); altered energy balance in response to sleep restriction; hormones in breast carcinogenesis; ecdysteriods and honeybee social behaviors; and changes in appetite-associated hormone and feeding behavior in advanced age.