This Encyclopedia provides a comprehensive overview of individual differences within the domain of personality, with major sub-topics including assessment and research design, taxonomy, biological factors, evolutionary evidence, motivation, cognition and emotion, as well as gender differences, cultural considerations, and personality disorders. It is an up-to-date reference for this increasingly important area and a key resource for those who study intelligence, personality, motivation, aptitude and their variations within members of a group.

Dr. Hill is a member of the faculty in the Department of Psychology at Oakland University, where he is the director of the Self and Interpersonal relationships Laboratory. He has published nearly 100 peer-reviewed journal articles, book chapters, and books.  His primary research interests are in self-esteem, narcissism, cognitive representations of the self, and interpersonal relationships.  He currently serves as Associate Editor for Self and Identity, Journal of Personality Assessment and Evolutionary Psychological Science.

Dr. Shackelford is Professor and Chair of the Department of Psychology at Oakland University, where he is Co-Director of the Evolutionary Psychology Lab. and where he created new doctorate and masters programs.  He has published about 300 peer-reviewed articles and chapters, and has edited fourteen volumes.  In all, his work has been cited over 10,000 times.