Risk is a concept we implicitly understand as human beings, and we discuss and evaluate it in many situations on a day-by-day basis. But what is the actual definition of risk? And what is considered an acceptable/tolerable risk? Does this concept change depending on the context, or has it an absolute meaning? How do we represent the risk? Lucia Capogna and Stephen Bull explore these questions and provide advice on some of the pitfalls that may be encountered when categorising and treating risk.