Risk has become one of the main topics in fields as diverse as engineering, medicine, and economics, and it is also studied by social scientists, psychologists, and legal scholars. But the topic of risk also leads to more fundamental questions such as:What is risk?What can decision theory contribute to the analysis of risk? What does the human perception of risk mean for society? How should we judge whether a risk is morally acceptable or not? Over the last couple of decades, questions like these have attracted interest from philosophers and other scholars into risk theory. This handbook provides an overview into key topics in a major new.