A homicide committed by a mentally disordered person who is under the care of health service professionals is a shocking event. Otherwise known as a ‘patient homicide’, these incidents are followed by an investigation into the care and treatment received by the perpetrator. These investigations are often regarded as a way to ‘learn lessons’, establish accountability and provide catharsis to families and the public. The book argues however that patient homicide events and the circumstances in which they occur are communicated about within closed systems of life (eg law, medicine). These systems operate according to unique internal logics. The communications produced by these systems, nevertheless, resonate in society and enable a diverse and complex space of governance to emerge – a space of governance in which universal understandings about patient homicides, health care, public safety and risk are unachievable. The Scottish Government initiated reform of their patient homicide investigation procedures in 2017 and plans to reform patient homicide investigations in England are slowly germinating. This original and compelling book is therefore a timely and important contribution. It concludes that health policy makers should re-evaluate their normative commitments to patient homicide risk reduction in a world of disharmony, objection and resistance.