This wide-ranging textbook provides a broad overview of the current state of animal behavior studies. It is an ideal textbook for undergraduate & graduate courses in biology experimental psychology & neuroscience. It comprises a series of contributions from international experts. It represents a diverse set of approaches to animal behavior. It ranges across the subject all levels from molecules & neurons to individuals & populations. It draws on the work of the pioneering Dutch ethologist Niko Tinbergen. It addresses all four of Tinbergens key questions: causation development function & evolution. It deals with contemporary subjects such as animal welfare conservation neurobiology & animal cognition.