Heng Choon (Oliver) Chan, Ph D is Associate Professor of Criminology at City University of Hong Kong, Hong Kong, SAR. His research focuses on stalking behavior, sexual homicide, offender profiling, sexual offending, homicide, and Asian criminology. He is the author of several books and more than 80 peer-reviewed journal articles and book chapters. Lorraine Sheridan, Ph D is a Chartered Forensic Psychologist and Associate Professor at Curtin University, Australia. The author of four books and numerous papers, she trains professionals involved in investigating stalking crimes and provides case management advice to police, security personnel, public figures, and others on stalking, harassment, violence, and risk and threat assessment.