Attachment and bonding are evolved processes; the mechanisms that permit the development of selective social bonds are assumed to be very ancient, based on neural circuitry rooted deep in mammalian evolution, but the nature and timing of these processes and their ultimate and proximate causes are only beginning to be understood. In this Dahlem Workshop Report, scientists from different disciplines -- including anthropology, psychology, psychiatry, and behavioral biology -- come together to explore the concepts of attachment and bonding from diverse perspectives. In their studies they seek...