Simon Ashby is very well placed through his long association with the Institute of Operational Risk to write what will prove to be the definitive book on operational risk. He challenges us to expand our understanding of operational risk to encompass 'unpredictable outcomes of the efficiency and effectiveness of operations.' Using a series of compelling case studies, he brings the subject alive. It is sobering to see how many of the selected case studies had underlying cultural drivers. I found the section on risk culture particularly practical in its insights to monitoring and taking action. The approach to operational risk event data establishes the benefits of learning from past events and ensuring recurrence is prevented, which surely is the essence of any robust approach to operational risk.