Editing a book can be an exciting and daunting process, but it is the excitement that keeps things going. We are very excited to have the opportunity to coordinate a volume showcasing new ideas and thinking in the linked fields of humanness and dehumanization. This derives from both the fascinating ideas of our contributors, and because it shows that this critical field of research is gaining broader recognition. Ideas about humanness are important in many sciences, ranging from biology to sociology, and are consequential in other fields, from religion to politics. However, the importance of beliefs about humanness is a relatively recent interest in psychology, even though it pervades many aspects of human functioning and interaction.