These notes are intended to help undergraduates who need to understand something of behavior both for its intrinsic interest and for their future careers in medicine, biology, psychology, anthropology, veterinary medicine, and nursing. In Emory University's Biology Department, a single-semester course called Evolutionary Perspectives on Behavior is given to undergraduates. It amounts to four, not eight months of study, so a great deal of compression is essential. There are several excellent textbooks available that deal with behavioral science from different perspectives, but we have found them too compendious for use in a short course when students are so heavily burdened; it is unsatisfactory to direct them to a chapter here and there in several different books or to this or that review article and original paper. In this volume, we have tried effectively and inexpensively to put in one place what we know is needed. The topics we have selected deal with their subjects in a simple, straightforward way without being too superficial. We could not cover everything and the gaps are not entirely idiosyncratic but reflect what students are given very well in other courses. Thus, there is no mention of the physiology of the axon and synapse; learning, memory, cognition, and basic genetics are hardly touched upon because students know about these matters from elsewhere.