Recent media coverage of the controversial theory of sexual violence as a product of biological evolution has once again brought the question of the origins of human motivation into the public eye. In this volume leading scholars in behavioural studies examine the value of evolutionary perspectives in understanding psychological motivations. Beginning with the fundamental fact that humans are part of the biological world, evolutionary psychologists contend that human motivations and mental processes should be understood as by-products of natural selection. By viewing human psychology - both normal and abnormal - within this framework, evolutionary psychologists intend to bridge the disciplinary divide between traditional psychology and fields such as biology. Daniel W. Leger is a professor of psychology and Alan C. Kamil is a professor of biology at the University of Nebraska, Lincoln. Jeffrey A. French is Kayser Professor of Psychology and Biology at the University of Nebraska, Omaha.