It is difficult to imagine a more heinous crime than the sexual abuse of children. Yet, terrifyingly, a new case of child sexual abuse is reported every seven minutes. In response to this crisis, self-appointed groups of citizens are fashioning themselves as pedophile hunters." Operating outside the law, these groups use social media to bait and expose those seeking to engage children sexually, both on- and offline. Their work has been remarkably effective, but at what cost? Following four years of unprecedented access to the UK's most prolific team of pedophile hunters, Mark de Rond offers balanced and insightful answers to the perplexing question of why these groups persist in using extreme methods to hold predators to account in view of less harmful alternatives. In doing so, he invites us to consider the societal impacts of pedophile hunters on our laws and institutions, as well as societal cohesion and safety. Contains mature themes.