The rate of injury and death inadvertently caused by medical treatment is too high and exacts enormous human and financial costs. Each year in Britain and the United States alone, hundreds of thousands of patients are injured, ten of thousands are killed and billions of dollars are spent on additional health care due to treatment-related harm. This book documents one of the first successful attempts to redesign error-prone medical systems, specifically drug administration in anaesthesia, according to the modern safety principles advocated by the Institute of Medicine and others in the human factors field. Safer systems will initially cost a little more - leading many hospital managers to conclude that they cannot afford to make their hospitals safer. However, harming patients during their treatment, and then having to treat them for such harm, is extraordinarily inefficient and expensive. The scope for savings by avoiding patient harm is therefore large, to say nothing of the reduction in human suffering. This book does not require the reader to be a specialist and will be of interest to anyone involved in system change or safety improvement in medicine.