Focusing on victims of online facilitated child sexual abuse, this book takes a rigorous approach to existing literature, addressing some of the most pressing public and policy questions today: which children are vulnerable to online facilitated child sexual abuse; how is their vulnerability made; what are they vulnerable to and how can resilience (both human and technical) be promoted? The book also probes the changing nature of child sexual abuse in the digital age: how is it the same or different and what does this mean for victims and survivors?  These questions are not only critical to developing effective responses that build resilience but are also central to debates about harm and cognitive justifications drawn on by both victims and offenders.