Dr Gwen Adshead is one of Britain's leading forensic psychiatrists. She treats serial killers, arsonists, stalkers, gang members and other individuals who are usually labelled 'monsters'. Whatever their crime, she listens to their stories and helps them to better understand their terrible acts of violence. Here Adshead invites the reader to step with her into the room to meet twelve patients and discover how minds can change. These men and women are revealed in all their complexity and shared humanity. Their stories make a powerful case for rehabilitation over revenge, compassion over condemnation. The Devil You Know will challenge everything you thought you knew about human nature.